Method of manufacturing a recess wall lined with bristles for a mouthpiece for simultaneously brushing at a plurality of dental positions, and a recess wall and mouthpiece obtained with the method; and dental cleaning device; and mouthpiece for brushing at a plurality of dental positions, brushing device comprising such mouthpiece, and method of operating such a mouthpiece or brushing device

ABSTRACT

The invention relates to method of manufacturing a recess wall lined with bristles for a mouthpiece for simultaneously brushing at a plurality of dental positions, and to a recess wall and mouthpiece manufactured according to the method. In a providing step, an elongate, continuous, bristled sheet part having a first side lined with a plurality of bristles is provided. The elongate sheet part defines a length axis extending parallel to the sheet part and, viewed transverse to the length axis, a cross-sectional shape. The sheet part obtained in the providing step has an initial condition in which the cross-sectional shape has an initial shape, and the length axis is arch-shaped. In a transforming step, the sheet part of the providing step is transformed from the initial condition to a final condition to provide the recess wall. In the final condition the cross-sectional shape has a final U-shape, the length axis is arch shaped, and the first side is a concave inner side of the final U-shape. The first side is in the final condition more concave than in the initial condition.

INTRODUCTION

This application relates to multiple inventions in the field of dentalcleaning devices for brushing teeth and/or dental positions. Morespecifically the multiple inventions relate to the field of dentalcleaning devices for simultaneously brushing at a plurality of dentalpositions.

The multiple inventions of this application are divided into 3 Chapters.

Chapter 1 corresponds to the priority application NL-2021332 filed on 17Jul. 2018, titled “Method of manufacturing a recess wall lined withbristles for a mouthpiece for simultaneously brushing at a plurality ofdental positions, and a recess wall and mouthpiece obtained with themethod.” As follows from this title, Chapter 1 is directed to especiallya method to manufacture a recess wall lined with bristles for amouthpiece. The present application claims the priority off NL-2021332.

Chapter 2 corresponds to the priority application NL-2021330 filed on 17Jul. 2018, titled “Dental cleaning device”. Chapter 2 is especiallydirected to operating the mouthpiece so that it performs his brushingaction. The present application claims the priority off NL-2021330.

Chapter 3 corresponds to the priority application NL-2021331 filed on 17Jul. 2018, titled “Mouthpiece for brushing at a plurality of dentalpositions, brushing device comprising such mouthpiece, and method ofoperating such a mouthpiece or brushing device”. Chapter 3 is especiallydirected to a specific configuration of the mouthpiece or recess wall.The present application claims the priority off NL-2021331.

The dental cleaning device of Chapter 2 may comprise a recess wallmanufactured with a method as described in Chapter 1, but this is notnecessarily the case. The recess wall of the cleaning device of Chapter2 may also have been manufactured in other manner.

Further, the dental cleaning device of Chapter 2 may have a mouthpieceor recess wall configured according to one of the embodiments of Chapter3, but this is not necessarily the case. The mouthpiece or recess wallof Chapter 2 may also be configured differently.

The mouthpiece of Chapter 3 may comprise a recess wall manufactured witha method as described in Chapter 1, but this is not necessarily thecase. The recess wall of the mouthpiece of Chapter 3 may also have beenmanufactured in other manner.

Further, the mouthpiece of Chapter 3 may be operated according toChapter 2, but this is not necessarily the case. The mouthpiece ofChapter 3 may also be operated in different manner.

The description of this application is arranged in accordance with these3 Chapters, as is also indicated in the description. The claims containheaders indicating to which Chapter the claims belong.

The Chapters use similar features corresponding terminology. In case ofdiscrepancy between terminology used in one Chapter and terminology usedin another Chapter, the terminology used in a Chapter prevails in thatChapter above terminology in other Chapters.

CHAPTER 1

Title: Method of manufacturing a recess wall lined with bristles for amouthpiece for simultaneously brushing at a plurality of dentalpositions, and a recess wall and mouthpiece obtained with the method.

The invention of Chapter 1 relates to the field of dental cleaningdevices having a mouthpiece for simultaneously brushing at a pluralityof dental positions, in particular to dental cleaning devices whereinthe mouthpiece is of the type comprising a body provided with at leastone recess delimited by a recess wall lined with a plurality of bristlesextending from the recess wall into the recess, the recess wall definingan arch-shaped length axis and, viewed transverse to the length axis, aU-shaped cross-sectional shape and being configured for encompassing aplurality of dental positions along a dental arch.

BACKGROUND OF THE INVENTION OF CHAPTER 1

Cleaning of teeth of humans and animals is a prerequisite for oralhealth, and health of internal organs. Various dental cleaning devicesare available, such as manual and powered toothbrushes. With thesetypical toothbrushes, it is advised to brush the teeth by a prescribedmethod for at least two minutes per day to effectively remove plaque.Yet, an average person does not spend all of the prescribed timecleaning his or her teeth, and does not always brush according to aneffective method. Additionally, for disabled or elderly persons orchildren it can be difficult to brush the teeth with a toothbrush, sincetypical toothbrushes require precise positioning of the brush bristleson various surfaces of the teeth. In case at some or all dentalpositions teeth are missing as is frequently the case with elderlypersons, cleaning of the gum at these dental positions is still aprerequisite for oral health, and health of internal organs.

There is a need to automatically brush the teeth and/or gum at thedental positions for cleaning the teeth and/or gum at these dentalpositions, whereby the time and effort required for effective brushingis reduced. In addition, there is a need to avoid carefully manoeuvringthe brush.

Dental cleaning devices are known comprising mouthpieces which cover themaxillary dental arch and/or the mandibular dental arch. Thesemouthpieces may be of the type comprising a body provided with at leastone recess delimited by a recess wall lined with a plurality of bristlesextending from the recess wall into the recess, the recess wall definingan arch-shaped length axis and, viewed transverse to the length axis, aU-shaped cross-sectional shape and being configured for encompassing aplurality of dental positions along a dental arch. The dental positions,like teeth and/or gum, to be brushed are inserted in the at least onerecess and the recess wall lined with bristles is operated to brush theteeth and/or gum with the bristles on the recess wall. Depending on thelength of the recess several or all dental positions of the maxillarydental arch and/or the mandibular dental arch may be brushedsimultaneously. An example of such a mouth piece can be found inPCT/NL2018/050276 filed on 27 Apr. 2018 by applicant. This PCTapplication was not yet been published at the priority dates of thepresent application.

A part of such a mouthpiece is the recess wall lined with bristles,which is in length direction arch-shaped and transverse to this lengthdirection U-shaped in cross-section, and which has the bristles at theinner side of the U-shape. The small inner space of the U-shapedcross-section and the arch-shaped length make the manufacturing of sucha recess wall lined with bristles quite difficult. Of course such arecess wall lined with bristles can be made manually by attaching thebristles or tufts of bristles one by one to the recess wall. This ishowever labour intensive and not time and cost efficient. Such a recesswall with U-shaped cross-section and bristles on the inner side of theU-shape may further be made by injection moulding the recess wall andbristles simultaneously, but, due to the small inner width of theU-shape, unloading the moulded recess wall and bristles from the mouldis hardly possible to deal with without damaging the bristles. Further,tufting the inner wall of a narrow, arch-shaped channel with U-shapedcross section cannot be automated.

Thus there is a need for a method of manufacturing a continuous recesswall lined with bristles for simultaneously brushing at a plurality ofdental positions arranged along an arch spanning a distance at leastequal to the distance from the left second pre-molar to the right secondpre-molar. In which the recess wall is configured for encompassing thedental positions associated with at least the left second pre-molar toat least the right second pre-molar and has a U-shaped cross section andan arch shaped length axis spanning a distance at least equal to thedistance from the left second pre-molar to the right second pre-molar.

SUMMARY OF THE INVENTION OF CHAPTER 1

It is an object of the invention of Chapter 1 to provide an alternativemethod of manufacturing a recess wall for a mouthpiece forsimultaneously brushing at a plurality of dental positions, the recesswall defining a narrow arch shaped channel having a U-shaped crosssection, having a length at least equal to the distance from the leftsecond pre-molar to the right second pre-molar, and being covered withbristles on the inner side of the channel.

According to a first aspect of the invention of Chapter 1, one or moreof the above objects are achieved by providing a method according toclaim 1.

According to the invention of Chapter 1 a method of manufacturing acontinuous recess wall lined with bristles for a mouthpiece forsimultaneously brushing at a plurality of dental positions is provided.In other words the method results in a recess wall which is configuredfor brushing at a plurality of dental positions at the same time. Incase a natural or artificial tooth element is present at the dentalposition where the bristles on recess wall brush, this tooth element isbrushed. In case a tooth element is absent at the dental position wherethe bristles on the recess wall brush, the gum may be brushed.

The continuous recess wall obtained with the method according to theinvention of Chapter 1 has an arch-shaped length axis and, viewedtransverse to the length axis, a U-shaped cross-section configured forencompassing said plurality of dental positions. The arch-shaped lengthaxis has a length which spans a distance at least equal to the distancefrom the left second pre-molar to the right second premolar. Further,the arch shaped length axis may have a shape similar to the shape of ahuman dental arch.

The method according to the invention of Chapter 1 comprises a providingstep. In this providing step, an elongate, continuous, bristled sheetpart having a first side lined with a plurality of bristles is provided.This elongate, continuous, bristled sheet part may be provided as aprefab part which has been pre-fabricated elsewhere, or, in theproviding step, a said elongate, continuous, bristled sheet part havingan arch shaped length axis and a first side lined with bristles may bemade, for example by assembling a sheet part and bristles to an integralpart, by injection moulding a sheet part and bristles, by injectionmoulding a sheet part in a mould in which bristles, for example ofnylon, have been placed as inserts to become an integral part with themoulded sheet part, or in any other manner suitable to obtain a sheetpart having a first side lined with bristles. The elongate, continuous,bristled sheet part obtained in the providing step has an initialcondition having an arch-shaped length axis extending parallel to thebristled sheet part and, viewed transverse to the length axis, aninitial shape as cross-sectional shape.

The method according to the invention of Chapter 1 further comprises atransforming step. In this transforming step, the bristled sheet partobtained in the providing step is transformed from the initial conditionto a final condition, resulting in the recess wall to be manufactured.In the final condition the cross-sectional shape has a finalU-shape—which may correspond to the U-shaped cross section of the recesswall to be manufactured —, the length axis is arch shaped, and the firstside is a concave inner side of the final U-shape. A furthercharacteristic of the final condition is that, in the final condition,the first side (of the bristled sheet part) which is lined with thebristles is more concave than in the initial condition.

This method allows the bristled sheet part with bristles to be providedin the providing step to be pre-fabricated elsewhere or made in situ ina condition that the first side of the sheet part, i.e. the side to belined with the bristles, is for example flat or convex or shallowconcave, so that it is easy accessible for making the bristled sheetpart. In the initial condition, the bristles may extend in essentiallythe same direction from the sheet part, the bristles may for exampleextend about parallel to each other. The bristles may also be grouped inone or more groups of parallel bristles, the bristles of differentgroups extending in different directions with respect to each other. Forexample a flat or convex first side of the sheet part in the initialcondition allows a mould half, in case of injection moulding the sheetpart and/or bristles, to be removed easily when unloading the mouldedsheet part and bristles, see for example DE 103.03.548 where a sheetpart with bristles for a conventional toothbrush is made by injectionmoulding the sheet part in several steps and inserting tufts of bristlesinto a mould half. Further a flat or convex first side of the sheet partin the initial condition also allows other techniques to be used forassembling a sheet part with bristles, like options offered by GBBoucherie NV, Belgium like the AFT toothbrush technology or technologiesof Zahoransky AG, Germany like anchorless toothbrushes. Thispre-assembled bristled sheet part is subsequently subjected to atransforming step, in which the initial condition of the bristled sheetpart is transformed to the recess wall to be manufactured, which recesswall to be manufactured has a final condition. In this transformingstep, the bristled sheet part obtained in the providing step is broughtto its final U-shaped cross section in which the bristles on opposingsides of the U-shaped cross section extend towards each other, and maycross each other.

According to a further embodiment of the invention of Chapter 1, thefinal U-shape may be defined by two legs and a bottom connecting theselegs, and a vertical axis may be defined as extending transverse to thebottom between the legs. According to this embodiment, the bristles onthe one leg and the bristles on the other leg may, in the finalcondition, extend from the respective leg towards each other. Furtheraccording to this embodiment, the bristles on the legs may, in additionor alternatively and viewed in the final condition, be provided at anangle with respect to the vertical axis, the angle being in the range of30° to 90° with respect to the vertical axis.

According to a further embodiment of the invention of Chapter 1, inwhich two legs and a bottom connecting these legs are defined by thefinal U-shape, a vertical axis is defined as extending transverse to thebottom, and the legs define, at each root of a said bristle on that leg,a tangent to the first side of the bristled sheet part, which tangentextends in a plane transverse to the length axis; in which the bristlesmay, in the initial condition, extend parallel to the vertical axis andeach said tangent may have a respective initial angle with respect tothe vertical axis; the legs are, in the transforming step, bendedtowards each other rotating each respective tangent through an angle ofx° with respect to the vertical axis such that the bristle associated tothe respective tangent extends at an angle of x° with respect to thevertical axis in a direction pointing away from the bottom. In case thelegs are straight and do not bend when bending the legs towards eachother, this further embodiment can also be phrased as an embodiment, inwhich two legs and a bottom connecting these legs are defined by thefinal U-shape and a vertical axis is defined as extending transverse tothe bottom; the bristles may, in the initial condition, extend parallelto the vertical axis; at least a part of said bristles on the legs may,in the final condition, extend at an angle of x degrees with respect tothe vertical axis in a direction pointing away from the bottom; the legsmay, in the initial condition, have an initial angle with respect to thevertical axis; and the legs may, in the final condition, have a finalangle with respect to the vertical axis, which is said x degrees largerthan the initial angle.

Doing so, i) the pre-fabricated part, i.e. the bristled sheet part, isprovided, in the providing step, with all bristles parallel to eachother and to the vertical axis which simplifies the making of thepre-fabricated part considerable. Next in the transforming step, thelegs are rotated through an angle of x degrees with respect to thevertical and towards each other, so that in the final condition thebristles on the legs extend at an angle of x degrees with respect to thevertical. The value for x may according to the invention of Chapter 1 bein the range of 0°-90°, such as in the range of 30°-60°, for example inthe range of 40°-50°. Additionally or alternatively, the final angle ofthe legs with respect to the vertical axis may according to theinvention of Chapter 1 be in the range of 0°-45°, for example in therange of 5°-20°.

According to a further embodiment of the invention of Chapter 1, theelongate, continuous, bristled sheet part having an arch shaped lengthaxis and a first side lined with bristles is made in the providing step.The providing step then may start with an (elongate, continuous) sheetpart (still without bristles) as a prefabricated part. This sheet partmay for example be made of TPE or any other suitable sheet part materialmentioned or not mentioned in this Chapter 1. Then during the providingstep, this—not yet bristled sheet part—is provided with bristles ortufts of bristles. These bristles respectively the bristles of the tuftsmay be made of Nylon or PBT (polybutylene terephthalate) or any othersuitable bristle material mentioned or not mentioned in this Chapter 1.The bristles or tufts of bristles will be fixed to the sheet part. Thisfixing of the bristles to the sheet part may be by tufting, adhering,fusing or any other method described or not described in this Chapter 1.The bristled sheet part thus obtained will subsequently be subjected tothe transforming step of the method according to the invention ofChapter 1.

According to a further embodiment of the invention of Chapter 1, thebristles having a root end, a free end and a bristle body extending fromthe root end to the free end, the bristled sheet part obtained in theproviding step is produced—in the providing step or prior to theproviding step—by tufting, the tufting comprising

-   -   inserting a plurality of nylon bristles or tufts of nylon        bristles through a first sheet part to extend with the bristle        body and free end from a front side of the first sheet part, and        to project with a root end at a back side of the first sheet        part;    -   optionally providing a second sheet part against the backside of        the first sheet part; and    -   fusing the root ends of the bristles with the first sheet part        and/or—in case present—the second sheet part.        The tufting may take place during the providing step, but a        tufted, bristled sheet part may also be a pre-fabricated part        delivered to the providing step. In the latter case the tufting        will already have taken place prior to the providing step, for        example at a much earlier time and/or at a different location        different from the location where the providing step takes        place. Providing the optional second sheet part may be by        injection moulding the second sheet part against the backside of        the first sheet part. Alternatively, the second sheet part may        be a pre-fabricated part which is placed against the backside of        the first sheet part and heated to get the roots fused to the        second sheet part. In absence of the second sheet part, the root        ends will be fixed to the first sheet, for example by fusing        them to the first sheet. In case the optional second sheet is        present, the roots are fixed to the first sheet part and/or        second sheet part, for example by fusing the roots to one or        both of the sheet parts. As such, the tufting may take place        according to a method already known, for example the method        described in DE 103.03.548.

According to a further embodiment of the invention of Chapter 1, thebristled sheet part may, in the transforming step, be transformed fromthe initial condition to the final condition by thermoforming. Thethermoforming may for example be done by vacuum forming. The bristledsheet part may be placed in a mould with the second side facing into aU-shaped mould cavity and the first side with bristles facing away fromthe U-shaped mould cavity, after which the mould cavity may be vacuumedcausing the bristled sheet part to be suctioned into the cavity andtaking the shape of the U-shaped cavity. When transforming the bristledsheet part from the initial condition to the final condition, thebristled sheet part may according to the invention of Chapter 1 bestretched by the thermoforming. According to a further embodiment thebristles may, in the final condition and viewed in the direction alongthe contour of the U-shape, be regularly distributed. Further inaddition or alternatively, the distribution of the bristles on thebristled sheet part may, in the initial condition, be configured suchthat, in the final condition and viewed in the direction along thecontour of the U-shape, the bristles are regularly distributed ordistributed according to a predetermined pattern. In other words, thepattern of the bristles in the initial condition is determined suchthat, taking into account the stretch of the sheet part occurring duringthe thermoforming, the predetermined pattern, such as a regulardistribution, is obtained in the final condition.

According to a further embodiment of the invention of Chapter 1, thelength axis may have a curvature which is in the initial condition thesame as in the final condition i.e. in the transforming step thecurvature of the length axis is not changed.

According to a further embodiment of the invention of Chapter 1, whereinthe length axis of the bristled sheet part may have an initial curvaturein the initial condition and a final curvature in the final condition,the initial curvature being curved wider than the final curvature. Inthe transforming step, the curvature of the length axis of the bristledsheet part will be reduced from the wide initial curvature to the narrowfinal curvature. Reducing the curvature of the length axis supports orpromotes the cross-sectional shape transforming to a more concave shapethan it had in the initial condition. In this respect, it may be helpfulwhen the cross-sectional shape of the bristled sheet part has, viewedwith respect to the first side of the bristled sheet part, already aconcave shape (which is less concave than in the final configuration).

According to a further embodiment of the invention of Chapter 1, inwhich the bristled sheet part has two boundary edges (delimiting thebristled sheet part and) extending along the length axis, optionallyparallel to the length axis, at, viewed in a direction transverse to thelength axis, a mutual distance from each other, the bristled sheet partmay, in the transforming step, be transformed by reducing the mutualdistance between the two boundary edges. Making use of the framemembers, the bow curvatures of the frame members may, in the initialcondition, either be wider than the final curvature of the bristledsheet part or correspond to the final curvature of the bristled sheetpart.

According to a further embodiment of the invention of Chapter 1, thebristled sheet part, obtained in the providing step, may be:

-   -   delimited by an inner boundary edge and an outer boundary edge,        extending along the length axis at a distance from the length        axis,    -   an integral part with a lingual frame member and facial frame        member both being bow-shaped along a respective bow curvature,        and    -   comprises, at the inner boundary edge, an inner attachment        member extending along the inner boundary edge, such as along        the entire inner boundary edge, and attached to the lingual        frame member, and, at the outer boundary edge, an outer        attachment member extending along the outer boundary edge, such        as along the entire outer boundary edge, and attached to the        facial frame member.

According to this further embodiment, the facial frame member andlingual frame member may be provided as one or two parts separate fromthe bristled sheet part, which are, after having provided in theproviding step, assembled together in the providing step. The providingstep may then comprise several sub-steps:

-   -   providing the facial frame member and the lingual frame member,    -   providing, separate from the facial and lingual frame member,        the bristled sheet part integral with the inner and outer        attachment member, and    -   attaching the inner attachment member and outer attachment        member to the lingual frame member respectively facial frame        member.        Alternatively, the bristled sheet part, the facial frame member        and the lingual frame member may according to this further        embodiment also be provided as a prefabricated integral part,        which may have been made at a very different location or a very        different moment in time. In other words the prefabricated        integral part comprising the bristled sheet part, facial frame        member and lingual frame member may so to say be the input of        the providing step as well as the output (=the bristled sheet        part obtained) of the providing step. The lingual and facial        frame member may be one integral frame member or two separate        frame member parts.

According to a further embodiment of the invention of Chapter 1, thebristled sheet part, the facial frame member and the lingual framemember are made, during the providing step or prior to the providingstep, by injection moulding, for example multi material injectionmoulding. According to a first example, tufts of bristles, for examplenylon bristles, may be placed in an injection moulding mould andsubsequently the material for forming the sheet part may be injected toover-mould the root parts of the tufts. According to a second example abristled sheet part—for example prefabricated according to the firstexample—may be placed in an injection moulding mould and the materialfor the lingual and facial frame members may be injected into the mouldto over-mould with a part of the sheet part, like an attachment member.According to a third example, the frame members—for exampleprefabricated by injection moulding—are placed in an injection mouldingmould and the bristle and sheet material may be injected to over-mouldwith the frame members or the sheet material may be injected toover-mould with both the tuft inserts (according to the first example)and the frame members. According to a fourth example, which may be incombination with the first example, the frame material for the facialand lingual frame member and the sheet material for the sheet partand—if not provided according to the first example—optionally thebristles may be injected into the mould to form the sheet part, andoptionally the bristles, and the lingual and facial frame member bysimultaneously or sequentially injecting the frame and sheet material.

According to a further embodiment of the invention of Chapter 1, theinner and outer attachment member may be configured as a side flapextending along the inner boundary edge respectively the outer boundaryedge and to be attached, for example adhered, to the lingualrespectively facial frame member. Adhering may be by means of anadhesive (or glue), by means of tape, by means of thermal welding or bymeans of a multi material injection moulding technique causing, at thelocation where the injected material for the frame members and theinjected material for the sheet part come together, a fused interfacelayer.

According to a further embodiment of the invention of Chapter 1, theinner and outer attachment member may be configured as a double sideflap extending along the inner boundary edge respectively the outerboundary edge, wherein the lingual and facial frame part are configuredwith a plate part, wherein the double side flap comprises a first flappart and a second flap part parallel to the first flap part and at adistance from the first flap part to define, between the first andsecond flap part, a gap configured to receive the plate part of thelingual respectively facial frame part. The plate parts inserted in thegap between the flaps will be attached to the flaps, for example byadhering. Adhering may be by means of an adhesive (or glue), by means oftape, by means of thermal welding or by means of a multi materialinjection moulding technique causing, at the location where the injectedmaterial for the frame members and the injected material for the sheetpart come together, a fused interface layer.

According to a further embodiment of the invention of Chapter 1, twosaid bristled sheet parts are obtained in the providing step, eachbristled sheet parts:

-   -   being delimited by a said inner boundary edge and a said outer        boundary edge, extending along the length axis at a distance        from the length axis,    -   being an integral part with a said lingual frame member and        facial frame member both being bow-shaped along a respective bow        curvature, and    -   comprising, on the inner boundary edge, a said inner attachment        member extending along the inner boundary edge and attached to        the lingual frame member, and, on the outer boundary edge, a        said outer attachment member extending along the outer boundary        edge and attached to the facial frame member,        wherein the facial frame member associated to a first of said        two bristled sheet parts is provided with a male or female part        of a first snap connection and the facial frame member        associated to a second of said two bristled sheet parts is        provided with a mating female respectively male part of said        first snap connection, and wherein the lingual frame member        associated to the first of said two bristled sheet parts is        provided with a male or female part of a second snap connection        and the facial frame member associated to the second of said two        bristled sheet parts is provided with a mating female        respectively male part of said second snap connection. Both the        female parts of the two snap connections may be provided on the        lingual and facial frame member of one said set, whilst the        mating male parts of the two snap connections are provided on        the lingual and facial frame member of the other said set.        Alternatively, the lingual frame member of the one set may be        provided with a female part of the first snap connection and the        facial frame member of the one set with a male part of the        second snap connection, whilst the lingual frame member of the        other set may be provided with a male part of the first snap        connection and the facial frame member of the other set with a        female part of the second snap connection.

According to a further embodiment of the invention of Chapter 1, the bowcurvatures of the lingual and facial frame members as obtained with thebristled sheet part in the providing step may, be wider than the finalcurvature; and the bow curvatures are, in the transforming step, reducedto correspondence with the narrower final curvature. Reducing the bowcurvatures of the frame members, after having attached the inner andouter edge of the bristled sheet part to a respective frame member is asimple action which is easy to automate. Reducing these bow curvatures,results in simultaneously reducing the curvature of the length axis ofthe bristled sheet part, which in turn results in increase of theconcavity of the first side of the bristled sheet part.

According to a further embodiment of the invention of Chapter 1, thelingual and facial frame members may be resilient and may have arelieved condition in which the frame members are stress-less and have abow curvature corresponding to the final curvature of the recess wall;the method may further comprise a pre-biasing step which takes placebefore or during the providing step; wherein, in the pre-biasing step,the frame members are pre-tensioned from the relieved condition to apre-tensioned condition in which the bow curvatures of the frame membersare widened to correspond to the initial curvature of the bristled sheetpart and in which the frame members have a pre-tension acting in adirection to return the frame members to their relived condition; andwherein, in the transforming step, the bow curvatures are reduced(narrowed) by releasing the pre-tension of the frame members. Doing so,the pretension built up in the frame members is used to increase of theconcavity of the first side of the bristled sheet part.

According to a further embodiment of the invention of Chapter 1, twosaid bristled sheet parts may be obtained and the attachment members ofa first and second sheet part may be attached to each other, for exampleby thermal welding. The attachment parts may be attached directly toeach other, for example by thermal welding, or indirectly via anintermediate part in which case thermal welding may be used as well.

According to a further embodiment of the invention of Chapter 1, whereinthe mouthpiece to be manufactured is of the type having two saidrecesses each delimited by a said recess wall lined with a saidplurality of bristles, wherein the arc shaped length axes of saidrecesses walls are parallel and the U-shaped cross-sectional shapes areopen in opposing directions;

the providing step may provide a first said bristled sheet part and asecond said bristled sheet part as one single part having a transitionarea connecting the first bristled sheet part integrally with the secondbristled sheet part, wherein the transition zone is configured to allowthe two bristled sheet parts to be folded with respect to each otherfrom a first position in which the two bristled sheet parts are alignedto a second position in which the two bristled sheet parts are foldedover each other; and wherein the method further comprises a folding stepin which the bristled sheet parts are folded with respect to each otherfrom the first to the second position. This folding step may take placebefore the transforming step, after the transforming step or during thetransforming step.

According to a further embodiment, the length of the length axis spans adistance at least equal to the distance from the left first molar to theright first molar, such as a length spanning a distance at least equalto the distance from the left second molar to the right second molar.

According to a further embodiment, the bristled sheet part obtained inthe providing step may be lined with at least 5 bristles per cm², suchas at least 10 bristles per cm². In case of for example elastomericbristles injection moulded together with the bristled sheet part, thebristled sheet part may be lined with 40 to 200 bristles per cm². Incase of for example bristles of nylon, the bristled sheet part may belined with 1000 to 6000 bristles per cm².

According to a further embodiment of the invention of Chapter 1, thefinal U-shape may have an internal width in the range of 0 to 10 mm,such as in the range of 2 to 12 mm; and/or the final U-shape has aninternal height in the range of 3 to 20 mm, such as in the range of 5 to10 mm.

According to a further embodiment of the invention of Chapter 1, thebristled sheet part has a thickness of up to 15 mm, such as a thicknessin the range of 0.5 to 3 mm, this thickness being defined as thethickness of the sheet part itself, i.e. without (the length of) thebristles.

According to a second aspect of the invention of Chapter 1, theinvention relates to a method of manufacturing a mouthpiece of the typecomprising a body provided with at least one recess delimited by arecess wall lined with a plurality of bristles extending from the recesswall into the recess, the recess wall defining an arch-shaped lengthaxis and, viewed transverse to the length axis, a U-shapedcross-sectional shape and being configured for encompassing a pluralityof dental positions along a dental arch; and wherein the recess wall ismanufactured according to the first aspect of the invention ofChapter 1. The bristled sheet part obtained in the providing step may beprovided as a part separate from the body Further, the bristled sheetpart obtained in the providing step may for example before, during orafter the transforming step, be attached to the body to become anintegral part of the body.

According to a further embodiment of the invention of Chapter 1, thebody may further comprise at least one pressure chamber configured forcontaining a fluid under pressure and wherein the body is configured todeform the recess wall by reciprocatingly increasing and decreasing apressure in the at least one pressure chamber. The body is configured todeform the recess wall by reciprocatingly (alternatingly) increasing anddecreasing the pressure in the at least one pressure chamber causing asustained repeating, reciprocating motion of the recess wall andbristles on that recess wall. The mouthpiece may comprise one, two,three, four, five, six, or any other number of pressure chambers whichcan be filled with a fluid, as explained in PCT/NL2018/050276, which isin the name of the same applicant and was not yet published at thepriority dates of the present application. By alternatingly(reciprocatingly) increasing a pressure in the at least one of thepressure chambers from a decreased pressure condition to an increasedpressure condition and decreasing the pressure in this pressurechamber(s) from the increased pressure condition to the decreasedpressure condition and sustained repeating this reciprocating motion,the recess wall carrying the optional bristles is brought into motionresulting in the recess wall respectively bristles acting at the dentalposition on the objects—teeth and/or gum present at these dentalpositions—to clean said objects.

According to a third aspect of the invention of Chapter 1, the inventionrelates to a mouthpiece obtained with the method according to the secondaspect of the invention of Chapter 1.

According to a fourth aspect of the invention of Chapter 1, theinvention relates to a recess wall for a mouthpiece for simultaneouslybrushing at a plurality of dental positions, wherein the recess wall isobtained by a method according to the first aspect of the invention ofChapter 1.

According to a fifth aspect of the invention of Chapter 1, the inventionrelates to a mouthpiece for simultaneously brushing at a plurality ofdental positions; wherein the mouthpiece is of the type comprising abody provided with at least one recess delimited by a recess wall linedwith a plurality of bristles extending from the recess wall into therecess, the recess wall defining an arch-shaped length axis and, viewedtransverse to the length axis, a U-shaped cross-sectional shape andbeing configured for encompassing a plurality of dental positions alonga dental arch; and wherein the recess wall is manufactured according tothe first aspect of the invention of Chapter 1.

According to the invention of Chapter 1, the sheet part—the part of thebristled sheet without the bristles—may be made from a plastic, forexample an injection mouldable or extrudable plastic. The plastic mayfor example be a thermoplastic elastomer.

BRIEF DESCRIPTION OF THE FIGURES OF CHAPTER 1

The invention of Chapter 1 will be explained further with reference tothe FIGS. 1-20. In these figures:

FIG. 1 shows a lower dental arch with dental positions and a system ofthree orthogonal axes defining a dental arch.

FIGS. 2a and 2b show an example of a mouthpiece with a recess wall madewith the method according to the invention of Chapter 1, wherein FIG. 2ashows a perspective view and FIG. 2b shows a cross-sectional viewaccording to the arrows IIb in FIG. 2 a.

FIG. 3 schematically shows a first method according to the invention ofChapter 1, FIG. 3a showing a bristled sheet part lined with bristles atone side, FIG. 3b showing mould for plastically deforming the bristledsheet part, FIG. 3c showing the bristled sheet part lying on top of themould before plastically deforming, FIG. 3d showing the bristled sheetpart after plastically deforming, and FIG. 3e showing the enlargeddetail Ille as indicated in FIG. 3 d.

FIG. 4 schematically shows an example of a recess wall formed with amethod according to the invention of Chapter 1.

FIG. 5 illustrates schematically a further providing step of a methodaccording to the invention of Chapter 1, providing two frame members.

FIG. 6 schematically shows the recess wall of FIG. 5 mounted in theframe members of FIG. 5, and illustrates another manner of doing thetransforming step of the method according to the invention of Chapter 1.

FIG. 7 shows, like FIG. 6, schematically the recess wall of FIG. 5mounted in the frame members of FIG. 5, and illustrates a further othermanner of doing the transforming step of the method according to theinvention of Chapter 1, wherein FIG. 7a shows the initial condition andFIG. 7b shows the final condition.

FIG. 8 schematically shows the combination of the manner of transformingaccording to FIG. 6 and the manner of transforming according to FIG. 7,the combination being performed simultaneously, wherein FIG. 8a showsthe initial condition and FIG. 8b shows the final condition.

FIG. 9 schematically shows two bristled sheet parts as one single partin a first state (FIG. 8a ) and in a second state (FIG. 8b ).

FIG. 10 schematically shows a relationship between the angle of the sideparts of the U-shape with respect to a vertical and the angle ofbristles with respect to the vertical, FIG. 10a showing an initialcondition and FIG. 10b showing a final condition.

FIG. 11 schematically illustrates the effects of two manners ofmechanically transforming the bristled sheet part from the initialcondition to the final condition, FIG. 11a showing, in perspective view,a bristled sheet part in the initial condition, FIG. 11b showing, inperspective view, the same bristled sheet part in the final condition,FIG. 11c showing cross-sectional views of a first location in initialand final condition, FIG. 11d showing cross-sectional views of a secondlocation in initial and final condition, and FIG. 11e showingcross-sectional views of a first location in initial and finalcondition.

FIG. 12 showing in cross-sectional view a further example of anembodiment according to the invention of Chapter 1, FIG. 12a showing aninitial condition, FIG. 12b showing a final condition, FIG. 12c showingtwo bristled sheet parts to be assembled together, and FIG. 12d showingthe two bristled sheet parts of FIG. 12 c in assembled condition.

FIG. 13 showing in cross-sectional view a further example of anembodiment according to the invention of Chapter 1, FIG. 13a showing aninitial condition, FIG. 13b showing another initial condition, and FIG.13c showing a final condition.

FIG. 14 showing in cross-sectional view a further example of anembodiment according to the invention of Chapter 1, FIG. 14a showing aninitial condition, and FIG. 14b showing a final condition.

FIG. 15 showing in cross-sectional view a further example of anembodiment according to the invention of Chapter 1, FIG. 15a showing afinal condition, FIG. 15b showing how frame members are attached to thebristled sheet, and FIG. 15c showing that frame members are attached tothe bristled sheet.

FIG. 16 showing in cross-sectional view a further example of anembodiment according to the invention of Chapter 1 in final condition,FIG. 16a showing a single sheet part assembly, and FIG. 16b showing howtwo such single sheet part assemblies may be attached to each other.

FIG. 17 showing in cross-sectional view a further example of anembodiment according to the invention of Chapter 1 in final condition,FIG. 17a showing two single sheet part assemblies, and FIG. 16b showinghow these two single sheet part assemblies may be attached to eachother.

FIG. 18 showing in cross-sectional view a further example of anembodiment according to the invention of Chapter 1 in final condition,FIG. 18a showing two single sheet part assemblies, and FIG. 16b showinghow these two single sheet part assemblies may be attached to eachother.

FIG. 19 showing in cross-sectional view a further example of anembodiment according to the invention of Chapter 1, FIG. 19a showing aninitial condition, FIG. 19b showing a final condition.

FIG. 20 showing in cross-sectional view a further example of anembodiment according to the invention of Chapter 1, FIG. 20a showing aninitial condition, FIG. 20b showing a final condition.

DETAILED DESCRIPTION OF THE FIGURES OF CHAPTER 1

The FIGS. 1-20 shows multiple embodiments of the inventions ofChapter 1. Although the embodiments may be different, the same referencenumbers/signs for same or similar items will be used throughout allthese FIGS. 1-20.

FIG. 1 shows in perspective view, highly schematically a part of anupper dental arch 1 with dental positions 2-14. Each dental position isindicated with a vertical dashed line. Each dental position usuallycomprises a tooth which is named according to a nomenclature known toeach dentist. Using this nomenclature:

-   -   dental position 2 is the position of the left ‘second molar’,        present in FIG. 1;    -   dental position 3 is the position of the left ‘first molar’,        missing in FIG. 1;    -   dental position 4 is the position of the left ‘second premolar’,        present in FIG. 1;    -   dental position 5 is the position of the left ‘first premolar’,        present in FIG. 1;    -   dental position 6 is the position of the left ‘canine’, present        in FIG. 1;    -   dental position 7 is the position of the left ‘lateral incisor’,        missing in FIG. 1;    -   dental position 8 is the position of the left ‘central incisor’,        present in FIG. 1;    -   dental position 9 is the position of the right ‘central        incisor’, present in FIG. 1;    -   dental position 10 is the position of the right ‘lateral        incisor’, present in FIG. 1;    -   dental position 11 is the position of the right ‘canine’,        present in FIG. 1;    -   dental position 12 is the position of the right ‘first        premolar’, present in FIG. 1;    -   dental position 13 is the position of the right ‘second        premolar’, present in FIG. 1;    -   dental position 14 is the position of the right ‘first molar’,        present in FIG. 1;        In FIG. 1 the dental position of the right ‘second molar’ is not        shown, and also the dental positions of the right and left        ‘third molar’, also called wisdom tooth, are not shown. Similar        the lower jaw has a similar number of dental positions, which        are in accordance with said nomenclature similarly named.

Reference number 15 indicates the lingual side of the arc of dentalpositions. The lingual side 15 is the inner side of the arc of dentalpositions, which inner side faces the tongue. Reference number 16indicates the facial side of the arc of dental positions. The facialside 16 is the outer side of the arc of dental positions, which outerside faces the face, like the cheeks and lips.

FIG. 1 further shows a system of three mutually orthogonal axes,comprising an x-axis X, an y-axis Y and a z-axis Z. The z-axis Z is acurved axis following the contour of the dental arch 1. The x-axis X andy-axis Y are perpendicular to each other and define an xy-plane which isessentially flat and perpendicular to the dental arch 1, i.e. eachxy-plane intersecting a location on the z-axis is, at that location,perpendicular to the curved z-axis Z. The z-axis Z defines a curvedlength direction. The z-axis Z and y-axis Y define a curved zy-plane,with viewed along the z-axis, an arc-shape similar to shape of thedental arc. Further, the z-axis Z and x-axis X define a zx-plane.

FIG. 2a shows schematically a perspective view of an example of amouthpiece 20 made with the method according to the invention ofChapter 1. FIG. 2b shows a cross section of the mouthpiece of FIG. 2a ,viewed as indicated by arrows IIb in FIG. 2 a.

The mouthpiece 20 comprises a body 21 provided with a first recess 22.This first recess 22 has, viewed along the z-axis of FIG. 1, a curvedlength direction and, viewed in the xy-plane of FIG. 1, an U-shapedcross section. The first recess 22 is delimited by a recess wall 23,which is in the xy-plane U-shaped. The recess wall 23 is lined with aplurality of bristles 24, each having one end, called the root 49,attached to the recess wall 23 and extending from the recess wall 23into the first recess 22.

Reference 26 indicates a nipple configured for connecting the mouthpieceto a pumping and/or suctioning device. The mouthpiece 20 further has aright half 27 and a left half 28, which halves come so to say togetherat nipple 26.

Reference 25 indicates a curved dividing line, which defines a mirrorplane parallel to the xz-plane as defined in FIG. 1. The mouthpiece asshown in FIG. 2 is so to say mirror symmetrical with respect to thismirror plane, meaning that there is a second recess (not visible in FIG.2a but visible in FIG. 2b ) opposite the first recess 22, which secondrecess is lined with bristles as well. It is noted that the first recessmay have a shape different than the shape of the second recess becausethe (teeth of the) upper and lower arc of dental positions havedifferent shapes.

The recesses 22 are configured to encompass an entire dental arch fromthe dental position of the right third or second molar to the dentalposition of the left third respectively second molar. The recesses 22may also be configured to encompass a part of an arch of dentalpositions, this part comprising at least five dental positions, forexample from the dental position of a central incisor to the dentalposition of a second premolar or to the dental position of a first molaror a dental position of a second molar.

FIG. 2b shows a cross-section according to arrows IIb in FIG. 2a of aright part of the mouth piece 20.

As can best be seen in FIG. 2b , the bristles may be provided as tufts29 of relatively thin bristles 24. Each tuft 29 may have a base 36 whichcarries the bristles 24 at their roots 19 and is attached to the recesswall.

As can be seen in FIG. 2b , the mouthpiece 20 has a body 21 having inits upper side a first recess 22 and in its lower side a second recess22. Both recesses 22 are delimitated by a flexible recess wall 23. Incross-section parallel to the xy-plane as defined in FIG. 1, the recesswalls 23 are U-shaped and have a recess wall bottom 34 and two recesswall legs 33 extending from the recess bottom wall. The recess wall 23is covered with tufts 29 of bristles on the legs 33 and/or bottom 34 ofthe recess wall.

Inside the body there is provided a pressure chamber 35, which may, viathe nipple 26 (FIG. 2a ), be filled with a fluid. The fluid may be agas, like air, or a liquid, like water. In the embodiment as shown inFIG. 2, the mouthpiece has one pressure chamber. It is however notedthat the mouthpiece may comprise a plurality of pressure chambers, like5 pressure chambers, or any other number of pressure chambers. The notpre-published PCT/NL2018/050276 shows examples of other numbers ofpressure chambers in FIGS. 4, 5, 7, 9 and 10. In case of multiplepressure chambers, all the pressure chambers or groups of pressurechambers may according to the invention of Chapter 1 be in fluidcommunication with each other, similar as is described in the notpre-published PCT/NL2018/050276.

As can be seen in FIG. 2b , the mouthpiece may comprise an internalsupport structure of a material which is rigid relative to the materialof the recess wall 23. This support structure may structure comprise alingual plate 30 and a facial plate 32, both extending along the curvedzy-plane defined in FIG. 1 and consequently, viewed along the z-axis,having a U-shape. In order to keep the lingual plate 30 and facial plate32 at a distance from each other, the support structure may comprise oneor more spacers 31. These one or more spacers 31 may for example be amultiple of bars or wires or a single plate which may extend essentiallyparallel to the zx-plane as defined in FIG. 1. In case of a single plateas spacer, this plate may divide the pressure chamber 35 in two pressurechambers, an upper one and a lower one. These two pressure chambers maybe in fluid communication with each other via one or more through holesthrough the plate. In case of large through holes and/or a large numberof through holes the two pressure chambers may effectively be one singlepressure chamber.

The mouthpiece as shown in FIG. 2 is configured for simultaneouslybrushing at a plurality of dental positions. In case a tooth is present,the tooth of the respective dental position will be brushed. Theremnants at a dental position, like the gum, may be brushed in case atooth may be missing and the teeth adjacent the location of the missingtooth may be additionally brushed by bristles intended for the locationof the missing tooth.

The single pressure chamber 35 comprises a first flexible recess wall 23delimiting the first recess 22 (the upper one in FIG. 2b ) and a secondflexible recess wall 23 delimiting the second recess 22 (the lower oneof FIG. 2b ). The first and second recess walls are deformable, inparticular by increasing or decreasing the pressure in the pressurechamber 23. The flexible recess walls 23 may be made from an elasticmaterial, such as a rubberlike material. The flexible recess walls 23may also be made from a non-elastic material. The material of theflexible recess walls 23 may keep a predetermined shape when there issubstantially no, or a low, pressure difference across an inner side andan outer side of the flexible recess walls 23.

The mouthpiece 20 is configured for the tufts 29 of bristles 24 toengage the tooth surface of teeth of a dental arch or, in case one ormore dental positions the tooth might be missing, to engage the gum atthe respective dental position(s) at least when the pressure in thepressure chamber 35 is increased. In case a tooth might be missing at adental position, especially the tufts 29 of bristles at the free ends ofthe recess wall legs 33 will engage the gum at the empty dentalposition.

Viewed in length direction Z of the dental arch—as defined in FIG. 1 —,the tufts 29 of bristles 24 may be arranged at about the same density asviewed in the cross-sections shown in FIG. 2 b.

When the pressure in the pressure chamber 35 is in increased to anincreased pressure condition, for example by feeding a fluid to thepressure chamber 35, or increasing an amount of fluid in the pressurechamber 35, the recess walls 23 are so to say compacted to narrow therecess 22, whereby the bristles 24, in particular the free ends thereof,may engage tooth surfaces firmly and/or may be deformed against toothsurfaces. When the pressure in the pressure chamber 35 is decreasedsubsequently, the recess walls are so to say widened to enlarge therecess 22. This narrowing and widening of the recess walls may be small,but when reciprocatingly repeated with some frequency of for example 1to 50 Hz, this reciprocatingly deforming of the recess wall byreciprocatingly narrowing and widening it, causes the bristles to movebetween a firmer and relatively less firm engagement with tooth surfacesand/or the bristles to alternate between a first and second deformedcondition, which in turn causes a sweeping and/or rubbing of bristlesalong the tooth surfaces. It is noted that the recess wall obtained withthe method according to the invention of Chapter 1 can also be used inother types of mouthpieces, for example mouthpieces without pressurechamber. The recess wall obtained with the method according to theinvention of Chapter 1 may for example be used in a mouthpiece where themouthpiece as a whole is mechanically vibrated to bring the bristlesinto brushing motion.

By a suitable cycle of increasing and decreasing pressure in thepressure chamber 35 an effective brushing action of the mouthpiece canbe obtained. The bristles 24 attached to the recess wall bottom 34generally perform an upward and downward motion during such cycling, andthe bristles 24 at the recess wall legs 33 generally perform a sidewaysmotion to and fro during such cycling in the direction of the x-axis asdefined in FIG. 1. Due to the recess 22 alternatively narrowing andwidening when reciprocatingly increasing and decreasing pressure, thebristles 24 at the recess wall legs may also be subjected to a back andforth pivoting around the z-axis as defined in FIG. 1, resulting in asweeping and/or rubbing movement of the bristles in the direction of they-axis as defined in FIG. 1.

Referring to FIG. 1, the width of a teeth element in the X directionvaries, depending on the dental position between about 2 to 12 mm.Taking into account that it is desired to keep the mouthpiece as smallas possible, the internal width of the U-shape of the recess wall in theX direction is to be kept as small as possible and may be about 0 to 2mm wider than the width of the respective tooth. By way of example togive some indication of dimensions, the internal width of the U-shape ofthe recess wall may, viewed in the X-direction of FIG. 1, be in therange of 0 to 20 mm, such as in the range of 2-12 mm. The bristles maybe up to 6 mm long. In case for example the bristles are 3 to 4 mm long.This means that between the bristles extending from opposing recess walllegs 33 no interspace or a limited amount of interspace of about 2-4 mmis left. In FIG. 2, these interspaces are shown exaggerated. Further byway of example to give some indication of dimensions, the U-shape of therecess wall may have, viewed in the Y-direction of FIG. 1, an internalheight in the range of 3 to 20 mm, such as in the range of 5 to 10 mm.These internal width and internal height measures are indicative for anadult human. For a child or for animals these measures might bedifferent. This limited amount of interspace makes it difficult tomanufacture a mouthpiece as shown in FIG. 2 in economical manner.Injection moulding for example is difficult due to the bristlesextending from the opposing recess wall legs extend essentially in the Xdirection which is transvers to the direction in which injectionmoulding moulds may be separated from each other after moulding.

FIG. 3 schematically shows a first method according to the invention ofChapter 1, FIG. 3a showing a sheet 100 with a bristled sheet part 101lined with bristles 104 at one side 102, FIG. 3b showing mould 110 forplastically deforming the bristled sheet part 101, FIG. 3c showing thebristled sheet part 101 lying on top of the mould 110 before plasticallydeforming, FIG. 3d showing the bristled sheet part 101 after plasticallydeforming, FIG. 3e showing enlarged the detail Ille of FIG. 3d , andFIG. 3c being the half on the left of axis 107 and FIG. 3d being thehalf on the right of the axis 107.

FIG. 3a shows a sheet 100, which may be made of a thermoplasticelastomer. A bristled sheet part 101 of this sheet 100 is indicated witha dashed inner arc 105 and a dashed outer arc 106. The shape of thesearcs 105 and 106 may correspond to the shape of an arc of dentalpositions as shown in FIG. 1. The sheet 100 and bristled sheet part 101have a first side 102, the upper side in FIG. 3, and an opposing secondside 103, the lower side in FIG. 3. The first side 102 of the bristledsheet part 101 is lined with bristles 104. It is noted that in FIG. 3,which is schematically, the bristles 104 are shown on the left half ofthe bristled sheet part 101, but that in practice also the right half ofthe bristled sheet part 101 and the top part of the bristled sheet part101 will be covered with bristles 104 as well.

FIG. 3a shows the bristled sheet part 101 as obtained in the providingstep. In this providing step, the bristled sheet part 101 is in aninitial condition. As shown in FIG. 3a , the bristles 104 extend in theinitial condition all in the same, upward, direction. The bristles 104may be essentially parallel to each other in the initial condition. Inthis initial condition the bristled sheet part 101 has, viewed in thexy-plane as defined in FIG. 1, a cross sectional shape, called ‘initialshape’ and, viewed along the z-axis as defined in FIG. 1, an arch-shapedlength axis. In FIG. 3a the bristled sheet part 101 is shown as part ofthe sheet 100, but it is to be noted that the rest of the sheet outsidethe dashed arcs 105 and 106 may be absent, for example may be cut away.In this case there will only be an arc shaped bristled sheet part 101and not a rectangular sheet 100 comprising the bristled sheet part 101.

In the initial condition as shown in FIG. 3, said ‘initial shape’ of thecross section of the bristled sheet part 101 is flat. The initial shapeof the first side 102 of the bristled sheet part 101 may however also beconcave (with the second side 103 being convex) or convex (with thesecond side 103 being concave).

FIG. 3b shows a mould 110 for transforming the bristled sheet part 101by thermoforming from the initial condition as shown in FIG. 3a to afinal condition. The mould 110 has, in its upper side 118, a cavity 111,which in the xy-plane as defined in FIG. 1 is U-shaped—see also atreference no. 112—and which, in the z-direction as defined in FIG. 1,extends along an arc similar in shape as the arc of dental positions.Several suction openings 113 may open into this cavity 111 (only onesuction opening is shown in FIG. 3b , but a multiple distributed overthe cavity 111 may be present). The cavity has on its upper side an arcshaped inner edge 115 and an arc shaped outer edge 116.

FIG. 3c , being the half on the left of axis 107, shows the sheet 100lying on top of the mould 110, with the bristled sheet part 101overlapping the cavity 111. The inner arc 105 and outer arc 106 may lieabove the inner edge 115 respectively outer edge 116 of the cavity. Theinner arc 105 and outer arc 106 may however have a largerdistance—viewed in the x-direction of FIG. 1, than the inner edge 115and outer edge 116, resulting in the inner arc 105 and outer arc 106lying on top of the upper surface 118 of the mould 110.

Starting from the state as shown in FIG. 3c , a suction may be appliedto the cavity 111 through the suction openings 113 or otherwise. Thissuction will transform the bristled sheet part 101, by thermoforming ofthe bristled sheet part 101, from its initial condition shown in FIGS.3a and 3c , to its final condition shown in FIGS. 3d and 3e to provide arecess wall 120—see also FIG. 4 —, which may be used as recess wall 29in the embodiment of FIG. 2. In this final condition, thecross-sectional shape of the bristled sheet part 101 has become a finalU-shape, the length axis is (still) arch shaped and the first side hasbecome a concave inner side of the final U-shape. In case in the initialcondition, the first side may already have been concave, the first sideof the bristled sheet part 101 will in the final condition be moreconcave than in the initial condition.

When plastically deform the bristled sheet part 101, the bristled sheetpart 101 may, viewed in a direction along the contour of the U-shape bestretched. In case, viewed in the final condition and viewed in thedirection along the contour of the U-shape, it is desired to have aneven distribution of the bristles, this stretching may be taken intoaccount when providing the bristled sheet part in the providing step byproviding the bristles in the providing step with a denser density andpossibly an uneven distribution configured such that it transforms to aneven distribution during the transforming step.

Referring to FIG. 3e and FIG. 2b , the final U-shape is defined by twoleg parts 33 and a bottom part 34 connecting these leg parts, wherein avertical axis 119 is defined as extending between the leg parts 33.

For clarity of the figure, FIG. 3d only shows schematically bristles 104on three locations. It will however be clear that the entire recess wallwill be covered with bristles. This may for example be, viewed along thez-axis defined in FIG. 1, a sequence of consecutive U-shaped bristlebows like shown in the detail of FIG. 3e . As can be seen in FIGS. 3dand 3e , the bristles 104 on the one leg part 33 and the bristles 104 onthe other leg part 33 extend from the respective leg part 33 towardseach other.

As can be seen in FIG. 3a , the bristled sheet part is a continuoussheet part. It has no cut outs facilitating transforming the bristledsheet part 101 from the initial condition (FIG. 3a ) to the finalcondition (FIGS. 3d and 3e ).

FIG. 4 shows a recess wall manufactured according to the method of theinvention of Chapter 1, for example a recess wall 120 as obtained withthe method according to FIG. 3. Like in FIG. 3d , the bristles 104 areshown only at the ends of the recess wall and in the middle of therecess wall, but, viewed along the Z-axis as defined in FIG. 1, theinner side of the recess delimited by the recess wall may be fullycovered with bristles 104.

FIG. 5 shows a ‘further providing step’ of the method according to theinvention of Chapter 1. In this ‘further providing step’ a lingual framemember 121 and a facial frame member 122 are provided. Both the lingualframe member 121 and the facial frame member 122 are bow shaped and bothhave an upper edge 125 respectively 126. Referring to FIG. 2b , thelingual frame member 121 may correspond to the lingual plate 30 and thefacial frame member 122 may correspond to the facial plate 32.

As indicated with the bold arrow A between FIG. 4 and FIG. 5, the recesswall 120 may, in a mounting step, be fixed to the lingual frame member121 and facial frame member 122. For this purpose, the inner edge 105(=dashed inner arc of FIG. 3) of the recess wall 120 is fixed on theupper edge 125 of the lingual frame member 121 and the outer edge 106(=dashed outer arc of FIG. 3) of the recess wall 120 is fixed on theupper edge 126 of the facial frame member 122. This results in thepicture of FIG. 6. After closing the gap between the lower edge 123 ofthe lingual frame member 121 and the lower edge 124 of the facial framemember 122 with a closure 127, a mouthpiece according to the inventionof Chapter 1 is obtained with a pressure chamber delimited by the facialframe member 122, the recess wall 120, the lingual frame member 121 andthe closure. When the vertical length, in the direction of the y-axis asindicated in FIGS. 1 and 4, of the lingual 121 and facial 122 framemembers is extended, the closure may be a further recess wall, turnedaround such that its opening faces downwards. One thus obtains amouthpiece like the one shown in FIG. 2. As shown in FIG. 2b , the outerfaces of the lingual and facial frame member may be coated, for examplein an injection moulding process, with a material the same as thematerial of the bristled sheet part.

As indicated with arrow V in FIG. 6, the curvatures of the lingual 121and facial 122 frame members may be reduced, for example by squeezingthe free ends of the bow-shaped frame members, after mounting the recesswall 120 to these frame members. Doing so will result, viewed in thedirection of the Y-axis of FIGS. 1 and 4, in an increase of the depth ofthe U-shaped cross section, in other words the bottom of the U-shapedcross section will come closer to the closure 127. This can in additionto the transforming by thermoforming of the method of FIG. 3 or as analternative for the transforming by thermoforming be used in order totransform the bristled sheet part 101 to its final condition. In case itis used as an alternative for thermoforming, the bristled sheet part 101may still be flat (like in FIG. 3a ) or slightly curved when in thestate as shown in FIG. 6. The transformation step then comprisesreducing the initial curvature of the bristled sheet part 101 to itsfinal curvature simultaneously with transforming the cross sectionalshape from its flat or slightly curved initial shape to its finalU-shape.

Referring to FIG. 6, the curvatures of the lingual and facial framemembers 121, 122 may also be realised by using resilient frame members121, 122. From a relieved or stress-less condition, in which the framemembers have a narrow bow curvature corresponding to their finalcurvature, the frame members 121, 122 may be pre-biased from therelieved condition to a pre-tensioned condition, in which the framemembers have a wider bow curvature than in the relieved condition, whichwider bow curvature may correspond to the initial curvature of thebristled sheet part. In this pre-tensioned condition, the frame members121, 122 have a pre-tension acting in a direction to return the framemembers 121, 122 to their relieved condition, which may correspond tothe final condition.

FIG. 7b shows a view similar to FIG. 6. FIG. 7a shows a side viewaccording to arrow Vila in FIG. 7b . FIG. 7a shows the bristled sheetpart 101 shown in its initial condition as it is obtained in theproviding step. In this initial position, the bristled sheet part 101 isflat, but the first side lined with the bristles 104 may also be shallowconcave or convex. FIG. 7b shows the bristled sheet part 101 in itsfinal condition. The bristled sheet part 101 is transformed from theinitial condition shown in FIG. 7a to the final condition shown in FIG.7b , by reducing, viewed in the direction of the x-axis as defined inFIG. 1 and also shown in FIG. 4, the distance between the inner edge 105(=dashed inner arc of FIG. 3) and outer edge 106 (=dashed outer arc ofFIG. 3) of the bristled sheet part 101 from the wider d2—see FIG. 7a —tothe smaller d1—see FIG. 7b —by moving the inner edge 105 and the outeredge 106 towards each other as indicated by the arrow C in FIG. 7b .Doing so will result, viewed in the direction of the Y-axis of FIGS. 1and 4, in an increase of the depth of the U-shaped cross section. Thismay be in addition to the transforming by thermoforming or may be usedas an alternative for the transforming by thermoforming in order totransform the bristled sheet part 101 to its final condition. In case itis used as an alternative for thermoforming, the bristled sheet part 101may still be flat (like is shown in FIG. 7a ) or slightly curved when inthe state as shown in FIG. 7a . In case the bristled sheet part 101 isattached to the upper edges of the frame members 121 and 122, thetransformation step may be carried out by reducing the distance betweenthe facial frame member 122 and lingual frame member 121 in thedirection of the x-axis—as defined in FIG. 1 and shown in FIG. 4 as well—.

The mechanisms described above in relation to FIGS. 6 and 7, in shortindicated as the arrow V mechanism (FIG. 6) and the arrows C mechanism(FIG. 7), both are basically a mechanical transformation. The arrow Vmechanism and arrows C mechanism may also be used in combination, theone after the other or simultaneously as shown in FIG. 8. In FIG. 8,FIG. 8a shows the initial condition having an arch shaped length axis L1and a distance d1 between the inner edge 105 and outer edge 106 of thebristled sheet part 101, and FIG. 8b shows the final condition having anarch shaped length axis L2 and a distance d2 between the inner edge 105and outer edge 106 of the bristled sheet part 101, wherein d2 is smallerthan d1 and L2 has a stronger/narrower curvature than L1.

FIG. 9 shows an example of two sheets parts 101 being provided as asingle part 150. FIG. 9a shows the single part in a flat condition. Thissingle part comprises two bristled sheet parts 101 having a first sidelined with bristles, the bristles on this first side being shown as agrey bow shaped face. The two bristled sheet parts are connected bytransition areas 151. These transition areas 151 are configured to allowthe two bristled sheet parts 101 to be folded with respect to each otherfrom a first position in which the two bristled sheet parts 101 arealigned—which first position is shown in FIG. 9a —to a second positionin which the two bristled sheet parts are folded over each other—whichsecond position is shown in FIG. 9b . The single part 150 may, in theproviding step, be provided in the state as shown in FIG. 9a or in thestate as shown in FIG. 9b , or in any intermediate state in between thestate of FIG. 9a and FIG. 9b . In case the single part 150 is providedin the state of FIG. 9a or in a said intermediate state, the bristledsheet parts 101 may, in a folding step, be folded from a first position(FIG. 9a or an intermediate state between FIGS. 9a and 9b ) to thesecond position (FIG. 9b ).

FIG. 10 shows in cross sectional view a further example of a bristledsheet part 101 in the initial condition (FIG. 10a ) and a bristled sheetpart 101 in the final condition (FIG. 10b ). The first side 102 ofbristled sheet part 101 is in the initial condition slightly concave.The bristled sheet part 101 has two leg parts 33 interconnected by abottom part 34. A vertical axis 160 extends transverse to the bottompart 34. In the initial condition, the bristles 104 extend parallel tothe vertical axis 160. The angle α of the leg parts 33 with respect tothe vertical axis 160 may, in the initial condition, for example be 55°.When, in the transforming step, the leg parts 33 are rotated towardseach other over an angle of x° with respect to the vertical axis 160,the resulting angle of the leg parts 33 with respect to the verticalaxis will become α−x° and the angle of each the bristles on the legs 33with respect to the vertical axis will become x°, see FIG. 10b .Assuming x may be 45° and a may be 55°, the final angle α−x° of the legparts 33 with respect to the vertical axis 160 will be 10°.

With respect to FIG. 10, it is noted that the bottom part 34 shows nobristles but that bristles 104 may be present on the bottom part 34 aswell. Further it is noted, that the leg parts 33 are, for reasons ofsimplicity of the FIG. 10 and the explanation of FIG. 10, shown asstraight, but these leg parts 33 may, in FIGS. 10a and 10b , be curvedas well, or may become curved in FIG. 10b starting from straight in FIG.10 a.

FIG. 11 schematically illustrates the effects of both narrowing thecurvature of the length axis of the bristled sheet part, and decreasingthe mutual distance d between the boundary edges 105 and 106 of thebristled sheet part 101, i.e. the distance d between the inner edge 105and outer edge 106 in the transforming step, by essentially mechanicaltransformation of the bristled sheet part 101. FIG. 11a shows aperspective view on the not bristled side of the bristled sheet part 101in the initial condition and FIG. 11b shows a perspective view on thenot bristled side of the bristled sheet part 101 in the final condition.As one can see from FIGS. 11a and 11b , the initial wide curvature ofthe length axis of the bristled sheet part 101 (see FIG. 11a ) is lesscurved than the final narrow curvature of the length axis of thebristled sheet part (see FIG. 11b ). FIG. 11c shows the cross-sectionalshape of the bristled sheet part 101 at location m in the initial state(on the left) and in the final state (on the right). FIG. 11d shows thecross-sectional shape of the bristled sheet part 101 at location n inthe initial state (on the left) and in the final state (on the right).FIG. 11e shows the cross-sectional shape of the bristled sheet part 101at location n in the initial state (on the left) and in the final state(on the right). As one can see from FIGS. 11c, 11d and 11e , the mutualdistance between the boundary edges 105 and 106 is reduced from d1 inthe initial condition to (the smaller) d2 in the final condition. Thistransformation may be performed without stretching the sheet part 101.When performing this transformation, one will notice that narrowing thecurvature of the length axis and the decrease of the mutual distance mayoccur simultaneously. As is illustrated in FIG. 11c , the crosssectional shape at position o will transform from a relatively shallowand blunt U-shape to a relatively deep and sharp U-shape, like aV-shape. As is illustrated in FIGS. 11d and 11e , the cross sectionalshape at the positions m and n will transform from a relatively shallowU-shape to a relatively deep U-shape. Positions m and n are in therelatively straight part of the arch shaped bristled sheet part andposition n is in the relatively most curved part of the arch shapedbristled sheet part. The cross-sectional shape changing, in the finalcondition (shown in FIG. 11b and right part of FIGS. 11c, 11d and 11e )and viewed from position m in the direction of position o, from bluntU-shaped to sharp U-shaped (V shaped) is in correspondence with thechange in cross-sectional shape of a human dental arch. In the humandental arch the central and lateral incisors may have, viewed in theplane perpendicular to the length direction of the human dental arch, anabout V-shaped cross-sectional shape, the molars and pre-molars have anabout U-shaped cross-sectional shape, whilst the canines have across-sectional shape in between the V-shape and U-shape.

FIGS. 12-18 schematically show some further examples of embodimentsaccording to the invention of Chapter 1. All these figures are incross-sectional view—the xy-plane as defined in FIG. 1—transverse to thearch-shaped length axis—extending in the direction of the z-axis of FIG.1 —. The cross-sectional views of FIGS. 12-18 are taken at the positionm of FIG. 11. Similar as in FIG. 11, the length axis of the bristledsheet parts 101 shown in FIGS. 12-18 is arch shaped, and similar as inFIG. 11, the cross-sectional shape of the bristled sheet parts 101 shownin FIGS. 12-18 may, in the final condition, vary along the arch-shapedlength axis.

The embodiment of FIG. 12 schematically shows an example of a relativelythick bristled sheet part 101 processed to a mouthpiece with the methodaccording to the invention of Chapter 1. FIG. 12a shows the bristledsheet part 101 in the initial condition as provided by the providingstep. The thickness of the sheet part is defined as the thickness of thesheet part itself without taking into account the bristles on the sheetpart and is indicated with g in FIG. 12a . In the example of FIG. 12 thethickness g is about 15 mm, whilst in the examples of other FIGS. 1-10and 12-18, the thickness g may for example be in the range of 0.5 to 3mm. FIG. 12b shows the bristled sheet part 101 after transformation tothe final condition, i.e. the recess wall as obtained. FIG. 12c showstwo said recess walls being brought together with the bottoms of theU-shapes facing each other. The bottoms of the U-shapes are subsequentlyjoined together at 130, for example by thermal welding or by means of anadhesive (or glue), resulting in the mouthpiece as shown in FIG. 12d .The mouthpiece shown in FIG. 12d may for example be used for brushingteeth by mounting the mouthpiece on a rod—which may be attached to themouthpiece at the location o of FIG. 11b —and subjecting this rod tovibrational movements in the length direction of the rod and/or in oneor two mutually perpendicular directions, each being perpendicular tothe rod.

The embodiment of FIG. 13 schematically shows, with two variants, anexample of a bristled sheet part assembly 201 processed to a recess wallwith the method according to the invention of Chapter 1. The sheet partassembly 201 comprises a bristled sheet part 101 delimitated, in thedirection of the arch shaped length axis, by the inner arc/(wall-)edge105 and outer arc/(wall-)edge 106. The sheet part assembly 201 furthercomprises, on the inner boundary edge 105, an inner attachment member231 extending along the entire inner boundary edge 105 and, on the outerboundary edge 106, an outer attachment member 232 extending along theentire outer boundary edge 106. Additionally, the sheet part assembly201 further comprises a lingual frame member 30 and a facial framemember 32. The inner attachment member 230 and outer attachment member232 may, as shown in FIG. 13, be shaped as a side flap projecting fromthe inner boundary edge 105 respectively outer boundary edge 106. Thelingual frame member 30 and facial frame member 32 may, as shown in FIG.13, be shaped as a plate.

The sheet part assembly 201 of FIG. 13 may, in the providing step, beprovided as a pre-fabricated part in the flat initial condition of FIG.13a , or in the U-shaped initial condition of FIG. 13b , or in aninitial condition in which the flaps 231, 232 and plates 30, 32 have anyother position relative to the bristled sheet part 101 and/or eachother. The pre-fabricated part may for example be made by injectionmoulding, such as a multi material injection moulding technique. Thesheet part assembly of FIG. 13 may also be made during the providingstep, for example by injection moulding, such as a multi materialinjection moulding technique.

Whether the sheet part assembly 201 is a pre-fabricated part which hasbeen made prior to the providing step or is made during the providingstep, in both cases it may be made by injection moulding, such as amulti material injection moulding technique. Tufts 29 (optionallyalready pre-assembled) with bristles 24 are placed as inserts in theinjection moulding mould, the roots of the tufts—which may optionally beprovided with a base 36 per tuft as shown —, projecting in the mouldcavity at the location where the sheet part 101 is to be formed. Afterclosing of the mould, a first and second plastic materials are injectedinto the mould. The first material forms the lingual 30 and facial 32frame member and the second material forms the sheet part 101 and innerattachment member 231 and outer attachment member 232. At the interfaces250 between the frame members 30, 32 and attachment members 231, 232,the frame members 30, 32 and attachment members 231, 232 will adhere toeach other due to the fused interface layer formed there. The secondmaterial forming the sheet part 101 over-moulds with the bases 36 of thetufts creating a firm bonding of the tufts to the sheet part 101. Thebonding of the bases 36 to the sheet part may for example be due toenclosing the bases within the sheet part and/or by fusing at theinterface of the second material and the bases 36. Alternatively, it isalso possible that the lingual and facial frame members have beenpre-fabricated and are, like the tufts, placed as inserts into theinjection moulding mould. In this case, there will be injected only thesecond material for forming the sheet part and attachment members whichmaterial will over-mould with the attachment members and adhere to theattachment members by a fused interface layer being formed.

The sheet part assembly 201 obtained in the providing step in theinitial condition of for example FIG. 13a or 13 b, is subsequentlysubjected to the transforming step. In this transforming step, which mayfor example be by thermoforming and/or mechanical deformation (forexample by narrowing the curvature of the length axis of the sheet partand/or reducing the distance between inner boundary edge 105 and outerboundary edge 106), the sheet part assembly 201 is transformed to itsfinal condition as shown in FIG. 13c . In the embodiment of FIG. 13, thetransforming step has been done by thermoforming. But as said, it mayalso be done by two manners of mechanical deformation or a combinationof these two manners and also thermoforming and mechanical deformationmay be combined in the transforming step.

As can be seen in FIG. 13c , the tufts/bristles 29/24 are, viewed in thecross-sectional plane, distributed in a regular pattern. Also in FIGS.13a and b , the tufts/bristles 29/24 are distributed in a regularpattern. Due to stretching of the wall part 101 during the transformingstep, the distance between the tufts/bristles 29/24 is in FIG. 13cincreased with respect to FIGS. 13a and 13b . In this example, thisstretch is regular over the U-shape, but this may also be irregular.Taking into account the stretch, the tufts/bristles can be arranged inthe initial condition of FIGS. 13a and 13b such that in the finalcondition of FIG. 13c , the tufts/bristles have a predetermined, likeregular, distribution.

The embodiment of FIG. 14 schematically shows another example of abristled sheet part assembly 201 processed to a recess wall with themethod according to the invention of Chapter 1. This embodiment isessentially the same as the embodiment of FIG. 13, except that in theembodiment of FIG. 14 the bristles are injection moulded from the samematerial as the sheet part, instead of tufts inserted into the injectionmoulding mould prior to injection moulding. For the rest, theelucidation given in relation to FIG. 13 applies mutatis mutandis toFIG. 14 as well.

The embodiment of FIG. 15 schematically shows another example of abristled sheet part assembly 201 processed to a recess wall with themethod according to the invention of Chapter 1. FIG. 15 is shown withtufts like in FIG. 13 but may equally well be with injection mouldedbristles 24 like in FIG. 12. The main difference between the embodimentof FIG. 15 and the embodiments of FIGS. 13 and 14, is in the innerattachment member and outer attachment member.

In FIG. 15 the inner and outer attachment member are formed as a doubleside flap extending along the inner boundary edge 105 respectively theouter boundary edge 106. The inner attachment member comprises a firstflap part 231 and a second flap part 233 parallel to the first flap part231 and at a distance from the first flap part 231 so that a gap 235 isdefined between the inner flap part 231 and outer flap part 233. Asindicated in FIG. 15b by arrows, the lingual frame plate 30 can beinserted into this gap 235. Similarly, the outer attachment membercomprises a first flap part 232 and a second flap part 234 parallel tothe first flap part 232 and at a distance from the first flap part 232so that a gap 236 is defined between the inner flap part 232 and outerflap part 234. As indicated in FIG. 15b by arrows, the facial frameplate 32 can be inserted into this gap 235.

FIG. 15a shows the sheet part assembly 201—not yet with the framemembers 30 and 32 included—in the initial condition as obtained in theproviding step. FIGS. 15b and 15c show the sheet part assembly 201 inthe final condition. As follows from FIG. 15b , first the transformationstep is applied to the sheet part assembly of FIG. 15a , without theframe members 30, 32, and subsequently the lingual frame member 30 andfacial frame member 32 are inserted into the respective gaps 235 and236. The frame members 30 and 32 may be attached to the outer flaps 231,232 and inner flaps 233, 234 by means of an adhesive (or glue) and/or bythermal welding.

With respect to the embodiment of FIG. 15 it is noted that thisembodiment may also be made by a combination of injection mouldingtechniques as elucidated in relation to FIG. 13 or in case the bristlesare according to FIG. 14 by a multi material injection mouldingtechnique in case the sheet part, flaps and frame members aresimultaneously or sequentially injection moulded in one mould orover-moulding in case the frame members have been made prior to mouldingthe sheet part and flaps (or the other way around in case the sheet partand flaps have been made prior to moulding the frame members).

The embodiment of FIG. 16 schematically shows another example of abristled sheet part assembly 201 processed, with the method according tothe invention of Chapter 1, to a mouthpiece with recess wall accordingto the invention of Chapter 1. The embodiment of FIG. 16 is basicallythe same as the embodiment of FIG. 14 so that the elucidation inrelation to FIG. 14 (and in relation to FIG. 13) applies mutatismutandis to FIG. 16 as well. It I further noted that the embodiment ofFIG. 16 may also use the double side flaps of FIG. 15, so that theelucidation in relation to FIG. 15 applies mutatis mutandis as well toFIG. 16. The difference of the FIG. 16 embodiment with respect to theembodiments of FIGS. 13-15 is in the lingual frame member 30 and facialframe member 32. These frame members are provided with a snap connectionallowing two sheet part assemblies 201 to be connected together.

FIG. 16a shows one of these sheet part assemblies in the initialcondition. FIG. 16b shows both sheet part assemblies 201 in the finalcondition. The sheet part assembly shown in FIG. 16a and in the upperhalf of FIG. 16b carries on the free ends of the lingual frame member 30and facial frame member 32 a female part 237, 238 of the snapconnection. The sheet part assembly shown in the lower half of FIG. 16bcarries on the free ends of the lingual frame member 30 and facial framemember 32 a male part 239, 240 of the snap connection. As will be clear,also the sheet part assembly shown in the lower half of FIG. 16b willinitially be provided in the initial condition similar to the one shownin FIG. 16a for the upper half of FIG. 16b . The male parts 239, 240 ofthe snap connection and the female parts 237, 238 of the snap connectionmate to each other such that a snap connection can be established. Aswill be clear, the male and or female parts of the snap connection areshown are intended as an example and may also be formed differently.

After assembling the sheet parts assemblies 201 of FIG. 16b together, amouthpiece according to the invention of Chapter 1 is obtained. Thebrushing action may be obtained by subjecting the entire mouthpiece to amechanical vibration, for example by means of a vibrating rod (orhandle) as mentioned earlier in relation to FIG. 12. The brushing actionmay also be obtained by using the space delimited by the lingual framemembers 30, facial frame members 32 and sheet parts 101 as a pressurechamber and reciprocatingly increasing and decreasing the pressure inthis pressure chamber.

The embodiment of FIG. 17 schematically shows another example of abristled sheet part assembly 201 processed, with the method according tothe invention of Chapter 1, to a mouthpiece with recess wall accordingto the invention of Chapter 1. The embodiment of FIG. 17 is basicallythe same as the embodiment of FIG. 16 so that the elucidation inrelation to FIG. 16 (as well as in relation to FIGS. 13-15) appliesmutatis mutandis to FIG. 16 as well. It I further noted that theembodiment of FIG. 17 may also use the double side flaps of FIG. 15,and/or may also have injection moulded bristles 24 such as in FIGS. 14and 16. The difference of the FIG. 17 embodiment with respect to theembodiment of FIG. 16 is in the lingual frame member 30 and facial framemember 32. These frame members are not provided with a snap connectionallowing two sheet part assemblies 201 to be connected together, butthis connection is established in different manner. In the embodiment ofFIG. 17, this connection is established by adhering, such as by anadhesive (or glue), and/or by thermal welding together the free ends ofthe lingual and facial frame members 30, 32 and/or the free ends of theflaps 231, 232 and/or the respective frame members with respective flapsto obtain a joint at 251 and 252.

The embodiment of FIG. 18 schematically shows another example of abristled sheet part assembly 201 processed, with the method according tothe invention of Chapter 1, to a mouthpiece with recess wall accordingto the invention of Chapter 1. The embodiment of FIG. 18 is basicallythe same as the embodiment of FIGS. 16 and 17 so that the elucidation inrelation to FIGS. 16 and 17 (as well as in relation to FIGS. 13-15)applies mutatis mutandis to FIG. 16 as well. It I further noted that theembodiment of FIG. 18 may also use the single side flaps of FIGS. 13, 14and 16, and/or may also have injection moulded bristles 24 such as inFIGS. 14 and 16. The difference of the FIG. 18 embodiment with respectto the embodiment of FIGS. 16 and 17 is in the lingual frame member 30and facial frame member 32. These frame members are not provided with asnap connection allowing two sheet part assemblies 201 to be connectedtogether and do not require an adhesive or thermal welding together. Inthe embodiment of FIG. 18, this connection is established an H-shapedframe member 260 comprising a lingual frame plate 30 and facial frameplate 32 interconnected by a spacer member 31. The spacer member 31 maybe a plate which is closed or provided with passages providing a fluidconnection between the upper half and lower half. Alternatively thespacer member 31 may be formed by a plurality of rods or wires or befully absent. In case the spacer member 31 is fully absent, only onelingual frame member 30 common for both the bristled sheet parts 201 isleft and only one facial frame member 32 common for both bristled sheetparts 201.

The embodiment of FIG. 19 schematically shows an further example of abristled sheet part assembly 201 processed to a recess wall with themethod according to the invention of Chapter 1. FIG. 19a shows the sheetpart in the initial position and FIG. 19b shows the sheet part in thefinal condition. FIGS. 19a and 19 b are identical to FIGS. 13b and 13c ,except that the bristles sheet part 101 of FIGS. 19a and 19b comprisestwo layers, a first layer 101 a and a second layer 101 b. The bristledlayer 101 of FIG. 19 comprises tufts 29 with nylon bristles. The firstlayer 101 a is provided with a passage for each tuft so that the rootsof the bristles reach (or project a little from) the backside of thefirst layer 101 a, which backside is in FIGS. 19a and 19b the lowerside. After the tufts of bristles have been inserted into the passages,the second layer 101 b is provided. This second layer fixes thebristles. Injection moulding the second layer, causes the root ends ofthe bristles fusing with the second layer which results in a reliableand firm bond. As will be clear, the bristled layer 201 of FIG. 19b mayalso be provided in the flat condition as shown in FIG. 13a . Further,it will be clear that the elucidation in relation to FIGS. 13a, 13b and13c applies mutatis mutandis to FIG. 19.

The embodiment of FIG. 20 schematically shows an further example of abristled sheet part assembly 201 processed to a recess wall with themethod according to the invention of Chapter 1. FIG. 20a shows the sheetpart in the initial position and FIG. 20b shows the sheet part in thefinal condition. FIGS. 20a and 20b are identical to FIGS. 13b and 13c ,except that in FIG. 20a the tufts are irregularly spaced whilst in FIG.20b they are regularly spaced. As is indicated in FIG. 20a , there is aninterspace Sc1 between the first and second tuft from the left, there isan interspace Sb1 between the fourth and fifth tuft from the left, andthere is an interspace Sa1 between the sixth and seventh tuft from theleft. As shown in FIG. 20a , Sa1 may be larger than Sb1 and Sb1 may belarger than Sc1. The relation between the interspaces Sa1, Sb1 and Sc1may however also be different, for example Sb1 may be equal to Sc1 andlarger than Sa1. As shown in FIG. 20b , the interspaces Sa1, Sb1 and Sc1have been increased to Sa2, Sb2 and Sc2, respectively. This increase maybe due to stretching of the sheet part 101 during the transformationstep. As shown in FIG. 20b , Sa2 may be equal to Sb2 and Sc2. Sa1, Sb1and Sc1 may have been chosen—taking into account the stretching of thesheet part during the transformation step —such that after thetransforming step Sa2 is equal to Sb2 and Sc2.

The next following clauses 1-39 give examples of the above describedinventions of Chapter 1 and further aspects and embodiments of theseinventions of Chapter 1:

-   -   1] Method of manufacturing a continuous recess wall lined with        bristles for a mouthpiece for simultaneously brushing at a        plurality of dental positions, the continuous recess wall having        an arch-shaped length axis and, viewed transverse to the length        axis, a U-shaped cross-section configured for encompassing said        plurality of dental positions, and the arch-shaped length axis        having a length which spans a distance at least equal to the        distance from the left second pre-molar to the right second        premolar;    -   wherein the method comprises a providing step, in which an        elongate, continuous, bristled sheet part having a first side        lined with a plurality of bristles is provided, the elongate,        bristled sheet part defining a length axis extending parallel to        the bristled sheet part and, viewed transverse to the length        axis, a cross-sectional shape, and    -   wherein the elongate, continuous, bristled sheet part obtained        in the providing step has an initial condition in which:        -   the cross-sectional shape has an initial shape, and        -   the length axis is arch-shaped;    -   wherein the method further comprises a transforming step, in        which the elongate, continuous, bristled sheet part obtained in        the providing step is transformed to a said continuous recess        wall having a final condition;    -   wherein in the final condition:        -   the cross-sectional shape has a final U-shape,        -   the length axis is arch shaped, and        -   the first side is a concave inner side of the final U-shape;            and    -   wherein the first side is in the final condition more concave        than in the initial condition.    -   2] Method according to clause 1,    -   wherein, in the final condition, the bristles from opposing        sides of the U-shaped cross section extend towards to each        other.    -   3] Method according to one of the clauses 1-2,    -   wherein the final U-shape is defined by two legs and a bottom        connecting these legs,    -   wherein a vertical axis is defined as extending transverse to        the bottom between the legs.    -   4] Method according to clause 3,    -   wherein, in the final condition, the bristles on the one leg and        the bristles on the other leg extend from the respective leg        towards each other.    -   5] Method according to clause 3 or 4,    -   wherein, in the final condition, the bristles on the legs are        provided at an angle with respect to the vertical axis, the        angle being in the range of 0° to 90°, such as in the range of        30° to 90°, with respect to the vertical axis.    -   6] Method according to one of the clauses 1-5,    -   wherein, in the initial condition, the first side of the        bristled sheet part is concave, flat or convex.    -   7] Method according to one of the clauses 1-6,    -   wherein two legs and a bottom connecting these legs are defined        by the final U-shape, a vertical axis is defined as extending        transverse to the bottom, and the legs define, at each root of a        said bristle on that leg, a tangent to the first side of the        bristled sheet part, which tangent extends in a plane transverse        to the length axis;    -   wherein, in the initial condition, the bristles extend parallel        to the vertical axis;    -   wherein, in the transforming step, the legs are bended towards        each other rotating each respective tangent through an angle of        x° with respect to the vertical axis such that the bristle        associated to the respective tangent extends at an angle of x°        with respect to the vertical axis in a direction pointing away        from the bottom.    -   8] Method according to clause 7,    -   wherein said x° is in the range of 0°-90°, such as in the range        of 30°-60° or in the range of 40°-50°.    -   9] Method according to clause 7 or 8,    -   wherein the final angle of the legs with respect to the vertical        axis is in the range of 0°-45°, such as in the range of 5°-20°.    -   10] Method according to one of the clauses 1-9,    -   wherein the elongate, continuous, bristled sheet part having an        arch shaped length axis and a first side lined with bristles is        made in the providing step.    -   11] Method according to one of the clauses 1-10,    -   wherein the bristles have a root end, a free end and a bristle        body extending from the root end to the free end;    -   wherein the bristled sheet part obtained in the providing step        is produced by tufting, the tufting comprising        -   inserting a plurality of nylon bristles or tufts of nylon            bristles through a first sheet part to extend with the            bristle body and free end from a front side of the first            sheet part, and to project with a root end at a back side of            the first sheet part;        -   optionally providing a second sheet part against the            backside of the first sheet part; and        -   fusing the root ends of the bristles with the first sheet            part and/or the optional second sheet part.    -   12] Method according to one of the clauses 1-11,    -   wherein the bristled sheet part is, in the transforming step,        transformed from the initial condition to the final condition by        thermoforming, such as vacuum forming.    -   13] Method according to clause 12,    -   wherein, viewed in a direction along the contour of the U-shape,        the bristled sheet part is stretched by the thermoforming.    -   14] Method according to clause 13,    -   wherein, in the final condition and viewed in the direction        along the contour of the U-shape, the bristles are distributed        according to a predetermined pattern.    -   15] Method according to clause 13 or 14,    -   wherein, in the initial condition, the distribution of the        bristles on the bristled sheet part is configured such that, in        the final condition and viewed in the direction along the        contour of the U-shape, the bristles are distributed according        to a predetermined pattern.    -   16] Method according to one of the clauses 1-15,    -   wherein the length axis has an initial curvature in the initial        condition and a final curvature in the final condition, the        initial curvature being wider than the final curvature.    -   17] Method according to one of the clauses 1-15,    -   wherein the length axis has a curvature which is in the initial        condition the same as in the final condition.    -   18] Method according to one of the clauses 1-17,    -   wherein the bristled sheet part has two boundary edges extending        along the length axis at, viewed in a direction transverse to        the length axis, a mutual distance from each other; and    -   wherein, in the transforming step, the bristled sheet part is        transformed by reducing the mutual distance between the two        boundary edges.    -   19] Method according to one of the clauses 1-18,    -   wherein the bristled sheet part, obtained in the providing step:        -   is delimited by an inner boundary edge and an outer boundary            edge, extending along the length axis at a distance from the            length axis,        -   is an integral part with a lingual frame member and facial            frame member both being bow-shaped along a respective bow            curvature, and        -   comprises, at the inner boundary edge, an inner attachment            member extending along the inner boundary edge and attached            to the lingual frame member, and, at the outer boundary            edge, an outer attachment member extending along the outer            boundary edge and attached to the facial frame member.

20] Method according to clause 19, wherein the providing step comprisesthe sub-steps:

-   -   providing the facial frame member and the lingual frame member,    -   providing, separate from the facial and lingual frame member,        the bristled sheet part integral with the inner and outer        attachment member, and    -   attaching the inner attachment member and outer attachment        member to the lingual frame member respectively facial frame        member.    -   21] Method according to clause 19,    -   wherein, in the providing step, the bristled sheet part, the        facial frame member and the lingual frame member are provided as        a prefabricated integral part.    -   22] Method according to one of the clauses 19-21,    -   wherein the bristled sheet part, the facial frame member and the        lingual frame member are made, in the providing step, by        injection moulding, such as multi-material injection moulding.    -   23] Method according to one of the clause 19-22,    -   wherein the inner and outer attachment member are configured as        a side flap extending along the inner boundary edge respectively        the outer boundary edge and to be attached to the lingual        respectively facial frame member.    -   24] Method according to one of the clauses 19-23,    -   wherein the inner and outer attachment member are configured as        a double side flap extending along the inner boundary edge        respectively the outer boundary edge,    -   wherein the lingual and facial frame part are configured with a        plate part,    -   wherein the double side flap comprises a first flap part and a        second flap part parallel to the first flap part and at a        distance from the first flap part to define, between the first        and second flap part, a gap configured to receive the plate part        of the lingual respectively facial frame part.    -   25] Method according to one of the clauses 19-24,    -   wherein, in the providing step, two bristled sheet parts are        obtained, each bristled sheet part:        -   being delimited by a said inner boundary edge and a said            outer boundary edge, extending along the length axis at a            distance from the length axis,        -   being an integral part with a said lingual frame member and            facial frame member both being bow-shaped along a respective            bow curvature, and        -   comprising, on the inner boundary edge, an said inner            attachment member extending along the inner boundary edge            and attached to the lingual frame member, and, on the outer            boundary edge, a said outer attachment member extending            along the outer boundary edge and attached to the facial            frame member,    -   wherein the facial frame member associated to a first of said        two bristled sheet parts is provided with a male or female part        of a first snap connection and the facial frame member        associated to a second of said two bristled sheet parts is        provided with the female respectively male part of said first        snap connection, and wherein the lingual frame member associated        to the first of said two bristled sheet parts is provided with a        male or female part of a second snap connection and the facial        frame member associated to the second of said two bristled sheet        parts is provided with a female respectively male part of said        second snap connection.    -   26] Method according to one of the clauses 19-25,    -   wherein the bow curvatures of the lingual and facial frame        members, as obtained with the bristled sheet part in the        providing step, are wider than the final curvature; and wherein,        in the transforming step, the bow curvatures are narrowed to        correspondence with the final curvature.    -   27] Method according to one of the clauses 19-26,    -   wherein the lingual and facial frame members are resilient and        have a relieved condition in which the frame members are        stress-less and have a bow curvature corresponding to the final        curvature of the recess wall;    -   wherein a pre-biasing step takes place before or during the        providing step;    -   wherein, in the pre-biasing step, the frame members are        pre-tensioned from the relieved condition to a pre-tensioned        condition in which the bow curvatures of the frame members        correspond to the initial curvature of the bristled sheet part        and in which the frame members have a pre-tension acting in a        direction to return the frame members to their relieved        condition; and    -   wherein, in the transforming step, the bow curvatures are        narrowed by releasing the pre-tension of the frame members.    -   28] Method according to one of the clauses 19-27,    -   wherein, in the providing step, two said bristled sheet parts        are obtained and wherein the attachment members of the first and        second sheet part are attached to each other, such as by        thermally welding.    -   29] Method according to one of the clauses 1-28,    -   wherein, in the providing step, two said bristled sheet parts        are obtained as a single part having a transition area        connecting a first of the two bristled sheet part integrally        with a second of the two bristled sheet part;    -   wherein the transition area is configured to allow the two        bristled sheet parts to be folded with respect to each other        from a first position in which the two bristled sheet parts are        aligned to a second position in which the two sheet bristled        parts are folded over each other.    -   30] Method according to clause 29,    -   wherein, in a folding step, the bristled sheet parts are folded        with respect to each other from the first to the second        position.    -   31] Method according to one of the clauses 1-30,    -   wherein the length of the length axis spans a distance at least        equal to the distance from the left first molar to the right        first molar, such as a length spanning a distance at least equal        to the distance from the left second molar to the right second        molar.    -   32] Method according to one of the clauses 1-31,    -   wherein        -   the final U-shape has an internal width in the range of 0 to            20 mm, such as in the range of 2 to 12 mm;    -   and/or        -   the final U-shape has an internal height in the range of 3            to 20 mm, such as in the range of 5 to 10 mm.    -   33] Method according to one of the clauses 1-32,    -   wherein the bristled sheet part has a thickness of up to 15 mm,        such as a thickness in the range of 0.5 to 3 mm.    -   34] Method of manufacturing a mouthpiece of the type comprising        a body provided with at least one recess delimited by a recess        wall lined with a plurality of bristles extending from the        recess wall into the recess, the recess wall defining an        arch-shaped length axis and, viewed transverse to the length        axis, a U-shaped cross-sectional shape and being configured for        encompassing a plurality of dental positions along a dental        arch; and    -   wherein the recess wall is manufactured according to one of the        clauses 1-33.    -   35] Method according to clause 34, wherein the body further        comprises at least one pressure chamber configured for        containing a fluid under pressure and wherein the body is        configured to deform the recess wall by reciprocatingly        increasing and decreasing a pressure in the at least one        pressure chamber.    -   36] Mouthpiece obtained with the method according to clause 34        or 35.    -   37] Recess wall for a mouthpiece for simultaneously brushing at        a plurality of dental positions, wherein the recess wall is        obtained by a method according to one of the clauses 1-33.    -   38] Mouthpiece for simultaneously brushing at a plurality of        dental positions, wherein the mouthpiece is of the type        comprising a body provided with at least one    -   recess delimited by a recess wall lined with a plurality of        bristles extending from the recess wall into the recess, the        recess wall defining an arch-shaped length axis and, viewed        transverse to the length axis, a U-shaped cross-sectional shape        and being configured for encompassing a plurality of dental        positions along a dental arch,    -   wherein the recess wall is manufactured according to one of the        clauses 1-33.    -   39] Mouthpiece according to clause 38,    -   wherein the body further comprises at least one pressure chamber        configured for containing a fluid under pressure and wherein the        body is configured to deform the recess wall by reciprocatingly        increasing and decreasing a pressure in the at least one        pressure chamber.

As follows from the above, the term ‘pressure chamber’ as usedthroughout this Chapter 1 is a chamber in which the pressure is changedbetween a decreased pressure condition and an increased pressurecondition. The decreased pressure condition and increased pressurecondition may both be a pressure below ambient pressure, i.e. a vacuumdefined as a pressure between 0 and 1 bar. Alternatively, the decreasedpressure condition and increased pressure condition may both be apressure above ambient pressure, or one of these pressure conditions maybe about ambient pressure whilst the other is below or above ambientpressure.

Where in this Chapter 1 the terminology ‘pressure in the pressurechamber’ or similar terminology is used, it is the ‘pressure of thefluid in the pressure chamber’. It is the pressure of the fluid whichacts on the recess wall to cause local deformation. The pressure of thefluid may for example be increased by supplying additional fluid intothe pressure chamber or decreased by allowing fluid to leave thepressure chamber.

Where in this Chapter 1 ‘thermal welding’ is used, this may be a thermalwelding technique:

-   -   where heat is generated by mechanical movement, for example        vibration welding and ultrasonic welding,    -   a technique using an external heat source, for example hot plate        welding, hot bar welding, and hot gas welding    -   a technique using electric and/or magnetic fields, for example        laser welding, infrared welding, induction welding, and        dielectric welding;    -   where a weld occurs during the moulding of a plastic or        thermoplastic material, for example welds occurring in injection        moulding or during compression moulding.

Where in this Chapter 1 the term multi material injection moulding isused, this may be any injection moulding technique in which an item ismade from two or more injection moulded materials which form an integralpart due to fusing together at an interface. These materials may beinjected into the mould simultaneously or sequentially. Additionally oralternatively, a sub-item may have been pre-fabricated by injectionmoulding a first material in a first mould cavity and later added as aninsert in a second mould cavity into which a second material is injectedand become integral with the sub-item, wherein the first and secondmould cavity may be arranged in one mould or in different moulds. Manyof these injection moulding techniques are known to the skilled man andfrequently are indicated under a variety of names for same or verysimilar multi material injection moulding techniques, for example multishot component injection moulding (with two or more components),multi-component injection moulding, co-injection moulding, andover-moulding. It is noted that the frequently used term ‘component’ inthese names, means the same as ‘material’.

Where in this Chapter 1 the terminology ‘bristled sheet part’ is used,this means a sheet part having a first side lined with a plurality ofbristles.

Where in this Chapter 1 the terms ‘wide’, ‘narrow’, ‘widening’ and‘narrowing’ are used in relation to a curvature, wide means a wide bendanalogous to a wide turn when driving a car and narrow means a narrowbend analogous to a narrow or tight turn when driving a car. Furthernarrowing means going from wide to narrow whilst widening means goingfrom narrow to wide.

Taking into account the shape of the various dental positions/naturalteeth, the shape of the U-shaped cross section may vary along the lengthdirection of the recess/recess wall. In the region of the upper and orlower incisors, the U-shaped cross section may for example be V-shaped.

CHAPTER 2 Title: Dental Cleaning Device

The present invention of Chapter 2 relates to a dental cleaning device,in particular to a dental cleaning device of the type that comprises amouthpiece having a recess which is U-shaped in cross section and whichmay have a curved length direction.

BACKGROUND OF THE INVENTION OF CHAPTER 2

Cleaning the teeth of humans and animals is a prerequisite for oralhealth, and health of internal organs. Various dental cleaning devicesare available, such as manual and powered toothbrushes. With thesetypical toothbrushes, it is advised to brush the teeth by a prescribedmethod for at least two minutes per day to effectively remove toothplaque. Yet, an average person does not spend all of the prescribed timecleaning his or her teeth, and/or does not always brush according to aneffective method.

Persons may e.g. exert too much pressure on tooth bristles duringbrushing the teeth, whereby not only the bristles wear rapidly andexcessively, but also the brushing process is not effective, teeth maybe damaged, and tooth gum may withdraw which has adverse consequencesfor the dental health.

Hence, there is a need for an improved dental cleaning device. Morespecifically, there is a need for a dental cleaning device whereinbrushing with an excessive pressure is prevented. Further there is aneed for a dental cleaning device with a higher degree of control of thebrushing action, to make it almost impossible to brush ineffectively.

U.S. Pat. No. 4,795,347 discloses, in one embodiment, a physical stop tolimit the movement of a wall to which bristles are attached. The stopprevents excessive pressures to be applied to tooth of the user. Inanother embodiment, U.S. Pat. No. 4,795,347 discloses the use of anadjustable 30 pressure setting valve. The valve relieves the pressure ina chamber when the maximally allowed pressure is exceeded.

WO2010076702 uses a pair of valves to control the pressure in a chamber.When a first valve is opened, an under-pressure (partial vacuum) iscreated under a membrane. When a second valve is opened, anover-pressure is created beneath said membrane.

The application PCT/NL2018/050276, by the same applicant, discloses anelectronic valve configured to control the pressure in a chamber of adental cleaning device. This PCT/NL2018/050276 was not yet published atthe priority dates of the present application.

A need for more efficient and/or improved dental cleaning deviceshowever remains.

SUMMARY OF THE INVENTION OF CHAPTER 2

According to a first aspect of the invention of Chapter 2, an improveddental cleaning device is provided, comprising:

-   -   a mouthpiece having a pressure chamber and a recess which is        U-shaped in cross section and delimited by a flexible and        deformable recess wall, the pressure chamber being configured        for containing a fluid under pressure;    -   optionally, a plurality of bristles, each attached to the recess        wall with one end thereof and extending from said recess wall        into the recess;    -   a pump unit arranged in fluid communication with said pressure        chamber, the pump unit being configured to reciprocatingly        increase and decrease a pressure in the pressure chamber between        an increased pressure condition and a decreased pressure        condition by pumping a volume of fluid into, respectively out        of, the pressure chamber, thereby deforming the recess wall and        moving the recess wall back and forth increasing respectively        decreasing the recess;    -   a pressure sensor configured to measure a pressure        representative of the pressure in the pressure chamber and to        produce a pressure signal representative of said pressure, and    -   a controller configured to generate a control signal;        wherein the pressure sensor and the controller are connected        such that the controller, in use, receives the pressure signal        from the pressure sensor and the controller and pump unit are        connected such that the pump unit, in use, receives the control        signal from the controller; wherein the controller is configured        to generate the control signal in dependence on the pressure        signal and the pump unit is configured to provide a delivery        into and/or out of the pressure chamber in response to the        control signal; and        wherein the controller is configured to reduce the delivery of        the pump unit when the pressure in the pressure chamber exceeds        a predetermined upper threshold.

According to the present invention of Chapter 2, the dental cleaningdevice comprises a pressure sensor and a controller. The pressure sensoris configured to measure a pressure representative of the pressure inthe pressure chamber. The pressure sensor may for example be arranged inthe pressure chamber, where it measures said pressure directly.Alternatively, the pressure sensor may be arranged in an inlet tube thatis arranged between the pump unit and the pressure chamber, e.g. nearthe pressure chamber, where it measures the pressure of the fluidentering the pressure chamber. From said pressure, the pressure in thepressure chamber may be calculated and/or estimated. Furtheralternatively, the pressure sensor may be arranged in an inlet tube thatis arranged between the pump unit and the pressure chamber, e.g. nearthe pump, where it measures the pressure of the fluid exiting the pumpunit. From said pressure, the pressure in the pressure chamber may becalculated and/or estimated. Yet alternatively, the pressure sensor maybe integrated with the pump unit, where it measures the pressure of thefluid exiting the pump unit. From said pressure, the pressure in thepressure chamber may be calculated and/or estimated.

While measuring the pressure in the pressure chamber, said pressure maybe compared to a reference pressure, such as the ambient pressure. Arelative pressure may then be measured, the measured pressure beingrelative to the reference pressure (ambient pressure). Alternatively, anabsolute pressure measurement may be taken, measuring the absolute valueof the pressure in the pressure chamber.

According to the invention of Chapter 2, the pressure sensor and thecontroller are connected. That is, the pressure sensor and thecontroller are arranged in communication with each other, and a signalcan be send from the pressure sensor to the controller (and/or viceversa). The connection may e.g. be a wired connection, or a wirelessconnection. The pressure sensor produces a pressure signal that isrepresentative of the pressure (in the pressure chamber) measured by thepressure sensor. This pressure signal is, in use of the dental cleaningdevice, send to the controller, which controller receives said signal.

According to the invention of Chapter 2, the controller is configured togenerate a control signal, in dependence of the pressure signal. Forexample, the control signal may indicate whether the pressure in thepressure chamber is too high, within pre-defined boundaries, or too low.A control signal may be generated continuously. For example, when thepressure signal indicates that the pressure in the pressure chamber istoo high (when the pressure exceeds a pre-set upper threshold), thecontrol signal may change with respect to the control signal that isgenerated when the pressure in the pressure chamber is within thepre-defined boundaries. Hence, the change in the control signal mayindicate that the function of the dental cleaning device is not asdesired. When the pressure signal indicates that the pressure in thepressure chamber is below the pre-set upper threshold, the controlsignal may have other characteristics. For example, the control signalgenerated when the pressure is below the pre-set upper threshold, mayindicate to the pump unit that the dental cleaning device is functioningas desired.

The control signal may alternatively be a switch-type signal, which isonly generated when the pressure exceeds the pre-defined threshold, orwhich is only generated when the pressure is within the desiredboundaries. Hence, the control signal may not be continuously generated.

According to the invention of Chapter 2, the controller and the pumpunit are connected. That is, the controller and the pump unit arearranged in communication with each other, and a signal can be send fromthe controller to the pump unit (and/or vice versa). The connection maye.g. be a wired connection, or a wireless connection When the controllerproduces a control signal said signal is, in use of the dental cleaningdevice, send to the pump unit, which pump unit receives said signal. Inresponse to said control signal, the pump unit provides a delivery intoand/or out of the pressure chamber.

Hence, upon performing its work, the pump unit delivers the fluid intoand out of the pressure chamber at a delivery of for example between 0and 4 litres per minute. The pump unit may be configured to deliver apre-set delivery (in litres per minute) of fluid into and out of thepressure chamber. When receiving the control signal, the pump unit maythen, respectively, continue its work at the present delivery, lower itsdelivery, or increase its delivery. In the case a too low pressure ismeasured in the pressure chamber, the delivery may be increased.Generating a control signal in dependence on the pressure signal mayensure that the pressure is kept below a predetermined upper threshold.Alternatively, the control signal may change when said upper thresholdis reached, indicating that the delivery of the pump unit is to bealtered.

According to the invention of Chapter 2, the controller of the dentalcleaning device is configured to reduce the delivery upon exceeding thepredetermined upper threshold. That is, the controller may be configuredto reduce the amount of air pumped into the pressure chamber by the pumpunit when the pressure in the pressure chamber exceeds an upperthreshold. As a result of reducing the delivery of the pump, thepressure in the pressure chamber drops, preventing the brushing of auser's teeth or gum with an excessive pressure while operating thedental cleaning device more efficiently—for example less powerconsumption which may result in less often recharging the battery —, andhence improving its working.

Further, by controlling the delivery of the pump via a control signalbased upon a pressure measurement, brushing teeth with an excessivepressure is prevented.

The dental cleaning device according to the invention of Chapter 2comprises a mouthpiece having at least one recess, which may e.g. be oneor two recesses. This at least one recess is U-shaped in cross-section.The mouthpiece comprises, per said recess, a recess wall delimiting therespective recess. The recess wall may be flexible and/or deformable.The recess wall may be formed from a sheet, which may for example bemade of a thermoplastic elastomer, a silicone elastomer, or a siliconpolymer. The recess wall is optionally lined with a plurality ofbristles, each having one end attached to the recess wall and extendingfrom the recess wall into the recess. In other words, the mouthpiece hasa recess, the recess wall of which may be covered with bristlesdistributed over the wall of the recess. At least one dental position,like a tooth element of this position or the gum covering the jawbone atthe location of the dental position, can be received in the recess, and,in case present, the bristles in the recess will be able to brush the atleast one dental position at both the lingual side (facing the tongue ofa user), the facial side (facing the lips/cheeks of a user), andpreferably also the free end face of the tooth (chewing surface/cuttingedge facing the opposite jawbone). Alternatively formulated, thebristles, if present, in use face towards teeth of a user. The bristlesmay be made of a nylon, an elastomer, or any other suitable material. Incase of a dental arch without teeth, the remaining arch of gum may needtreatment as well. In this case the gum may be massaged by a recess wallwith or without bristles. For improved cleaning of the gum, a cleaningfluid may be used in such a mouthpiece without bristles.

The mouthpiece according to the invention of Chapter 2 has at least onepressure chamber configured for containing a fluid under pressure, whichpressure can be increased and decreased. The body is configured todeform the recess wall by reciprocatingly (alternatingly) increasing anddecreasing the pressure in the at least one pressure chamber causing asustained repeating, reciprocating motion of the recess wall and, ifpresent, bristles on that recess wall. The mouthpiece may comprise one,two, three, four, five, six, or any other number of pressure chamberswhich can be filled with a fluid, as explained in PCT/NL2018/050276,which is in the name of the same applicant and was not yet published atthe priority dates of the present application. By alternatingly(reciprocatingly) increasing a pressure in the at least one of thepressure chambers from a decreased pressure condition to an increasedpressure condition and decreasing the pressure in this pressurechamber(s) from the increased pressure condition to the decreasedpressure condition and sustained repeating this reciprocating motion,the recess wall carrying the optional bristles is brought into motionresulting in the recess wall respectively bristles acting at the dentalposition on the objects—teeth and/or gum present at these dentalpositions—to clean said objects.

The recess is delimited by a recess wall. For example a flexible anddeformable recess wall which may delimit a part of the pressure chamberas well, i.e. be also a wall of the pressure chamber. It isalternatively however also possible that the recess wall is formed byone or more stiff pressure plates.

With respect to the terminology ‘increased pressure condition’ and‘decreased pressure condition’, it is noted that these conditions arerelative to each other, i.e. in the decreased pressure condition thepressure is decreased (lower) with respect to the increased pressure,and vice versa. In both conditions, the pressure may be lower than theambient pressure.

The length of the mouthpiece, measured in a direction transverse to theU-shaped cross-section and along a dental arch of a user, may beapproximately equal to the width of a human or animal tooth. A user ofthe dental cleaning device may then move it along the dental arch thatis to be brushed, e.g. first along the mandibular dental arch and thealong the maxillary dental arch, or vice versa. The length of themouthpiece may alternatively be at least the length of five teeth, suchthat at least five dental positions may be brushed at the same time. Forexample, the length of the mouthpiece may, measured in a directiontransverse to the U-shaped cross-section and along a dental arch of auser, measure a length which spans:

-   -   a distance at least equal to the distance from the left second        pre-molar to the right second pre-molar of a dental arch of a        human, such as an adult human;    -   a distance at least equal to the distance from the left first        molar to the right first molar of a dental arch of a human, such        as an adult human; or    -   a distance of substantially the full length of the dental arch        of a user (i.e. at least the arch from the left second molar to        the right second molar), such that the entire dental arch may be        brushed at the same time.        Further in addition, the arch-shaped length axis may have a        shape similar to the shape of a human dental arch or similar to        at least part of the shape of a human dental arch.

The dental cleaning device according to the invention of Chapter 2further comprises a pump unit arranged in fluid communication with saidpressure chamber, the pump unit being configured to reciprocatinglyincrease and decrease a pressure in the pressure chamber between anincreased pressure condition and a decreased pressure condition bypumping a volume of fluid into, respectively out of, the pressurechamber, thereby deforming the recess wall and moving the recess wallback and forth increasing respectively decreasing the recess. The pumpunit thus has a pumping action which sustained repeats increasing anddecreasing of the pressure in the pressure chamber. For example, thepump unit may comprise a pumping device configured to pump a fluid inthe pressure chamber, and a suction device configured to suck fluid outof the pressure chamber to alternatingly (reciprocatingly) increase anddecrease the pressure in the pressure chamber between said increasedpressure condition and said decreased pressure condition. Byalternatingly moving the recess wall back and forth, increasingrespectively decreasing the recess, teeth and/or gum of the user isbrushed, to improve the oral health of the user.

In a further embodiment of the first aspect of the invention of Chapter2, the pump may be configured to operate at a predetermined operatingfrequency, such as within a narrow frequency range around thispredetermined operating frequency. Alternatively, the controller may beconfigured to operate the pump at a predetermined operating frequency,such as within a narrow frequency range around this predeterminedoperating frequency. Further alternatively or additionally, theconfiguring of the controller ‘to reduce the delivery of the pump unitwhen the pressure in the pressure chamber exceeds a predetermined upperthreshold’ is such that a change of the operating frequency isprevented.

Depending on design parameters such as bristle length, stiffness of thebristle, characteristics of the flexible and deformable recess wall,etc., the brushing/cleaning action of the dental cleaning device may beoptimal at a certain operating frequency. Preferably, the dentalcleaning device is operated AT that operating frequency (thereciprocating increasing and decreasing of the pressure in the pressurechamber occurs at that operating frequency) when using the dentalcleaning device, also after the control signal has indicated that theupper pressure threshold is reached. For example, in case the fluid inthe pressure chamber is a gas, the reciprocating increasing anddecreasing of the pressure in the pressure chamber might at higherfrequencies become ineffective for getting the recess wall into motionand unpleasant for the user. This also applies in case the fluid is aliquid. Further, in case a flexible and deformable recess wall is usedthe recess wall might not deform in response to reciprocatinglyincreasing and decreasing of the pressure in the pressure chamber athigher frequencies.

Therefore, when altering the working of the dental cleaning device aftersaid indication, the operating frequency, at which the pump unitoperates or is operated, is according to this further embodimentunaltered such that the pump operates at a predetermined operatingfrequency.

Said predetermined operating frequency may be a fixed value of forexample 8 Hz. Although it may according to the invention of Chapter 2 bethe intention to control the delivery of the pump without affecting theoperating frequency of the pump, as a side effect of control actionsripples in the operating frequency may occur, for example with a fixedpredetermined operating frequency of 8 Hz, ripples in the range of ±0.5to ±1 Hz may occur.

Said predetermined operating frequency may also vary as a function oftime. In other words, the pump unit may have an operating frequencywhich varies according to a predetermined function of the time measuredas from switching on the pump. In a formula this reads as f_(t)=x(t).Every time the pump is switched on, the predetermined function willstart again at t=0. x(t) is a predetermined continuous or discontinuousfunction of the time. For example, the operating frequency may start att=0 with a low frequency, then rise to a higher frequency and at theend—for example after 20-30 seconds—slow down to a lower frequency.Starting with a low frequency may prevent the user from giving a startleresponse when switching on the pump and ending with a low frequency maygive the user an indication that the brushing is almost completed,whilst in between the frequency may be optimal for a good brushingresult. Also here it is noted that, although it may according to theinvention of Chapter 2 be the intention to control the delivery of thepump without affecting the operating frequency of the pump, as a sideeffect of control actions ripples in the operating frequency may occur,for example ripples in the range of ±0.5 to ±1 Hz may occur.

Said predetermined operating frequency may—both in the case of a fixedoperating frequency and in the case of an operating frequency varyingwith time—be in the range of 0.5 to 20 Hz.

In another further embodiment of the first aspect of the invention ofChapter 2, the upper threshold is at most 2 bar relative to ambientpressure, such as at most 1 bar relative to ambient pressure. A too highpressure in the pressure chamber may result in an uncomfortable userexperience for a user of the dental cleaning device, and may easilyresult in an excessive brushing force. Additionally, a too high pressuremay cause rupture of the recess wall, possibly resulting in harming theuser and/or economic loss of the dental cleaning device. The mentionedupper threshold of at most 2 bar relative to ambient pressure may besufficiently low in order to omit these adverse effects. Preferably, theupper threshold is at most 0.3 bar relative to ambient pressure (1.3times the ambient pressure), such as at most 0.2 bar relative to ambientpressure (1.2 times the ambient pressure). At such pressures, thebrushing action of the dental cleaning device is still sufficient, whilelowering the risk of injuring gum of the user, and the other adverseeffects mentioned.

It is noted that a direct pressure measurement, wherein the absolutepressure is measured, may be difficult to achieve in a dental cleaningdevice according to the invention of Chapter 2. It is foreseen thatinstead of measuring the absolute pressure, a comparison with areference pressure, e.g. the ambient pressure, is made to determine thepressure in the pressure chamber. Hence, the e.g. the wording “0.3 barrelative to ambient pressure” may alternatively mean “approximately 1.3times ambient pressure”, or “an approximate pressure of 1.3 bar”,depending on the specific measurement taken. It is commonly known thatambient pressure depends e.g. on geographic location, height, andweather conditions, and is about 1 bar everywhere on the earth.

In still another further embodiment of the first aspect of the inventionof Chapter 2, the controller may be further configured to increase thedelivery of the pump unit when said pressure in the pressure chamberfalls below a predetermined lower threshold, e.g. in the increasedpressure condition and/or decreased pressure condition. Similar to thesituation in which the pressure in the pressure chamber is too high,also a too low pressure may adversely affect the working of the dentalcleaning device. For example, when the pressure is too low, the bristlesof the dental cleaning device may not rub against the teeth of the userwith a sufficient force, resulting in an insufficient cleaning/brushingof the teeth. Therefore, the delivery, and thus also the pressure in thepressure chamber, is, according to this another further embodiment,increased when the pressure in the pressure chamber falls below saidlower threshold.

In an elaboration of this another further embodiment, the value of thelower threshold may be 1 bar or less below the value of the upperthreshold. That is, the maximum pressure difference in the pressurechamber, allowed by the controller, may be 1 bar or less. For example,when the upper threshold is 1.3 bar (ambient pressure plus 0.3 bar), thelower threshold may be 0.3 bar (ambient pressure minus 0.7 bar). Forexample, the difference between the values of the upper threshold andthe lower threshold may be 0.4 bar. The nominal pressure differencebetween the decreased pressure condition and the increased pressurecondition may however be less or substantially less than the differencebetween the values of the upper and lower threshold. That is, the upperand lower threshold may not be reached every pressurization cycle. Forexample, when the difference between the values of the upper and lowerthreshold is 0.4 bar, the nominal pressure difference between theincreased and decreased pressure condition may be only 0.1 or 0.2 bar.

In another elaboration of this another further embodiment, the lowerthreshold may be in the range of −0.5 to +0.2 bar relative to ambientpressure (0.5-1.2 times the ambient pressure), such as in the range of−0.5 to 0 bar relative to ambient pressure (0.5-1 times the ambientpressure). Hence, the pressure in the pressure chamber may be belowambient in the decreased pressure condition, while the pressure in thepressure chamber may be above ambient pressure in the decreased pressurecondition.

According to a second aspect of the invention of Chapter 2, a dentalcleaning device for simultaneously brushing at a plurality of dentalpositions is provided, which device comprises:

-   -   a mouthpiece having a pressure chamber and a recess delimited by        a recess wall which may be flexible and deformable, the recess        having a curved length direction and a U-shaped cross-section        transverse to the length direction, the recess being configured        for encompassing, viewed in the curved length direction, that        part of the dental arch of a user which extends from at least        the left second pre-molar to at least the right second premolar,        and the pressure chamber being configured for containing a fluid        under pressure;    -   optionally, a plurality of bristles, each having one end        attached to the recess wall and extending away from the recess        wall into the recess; and    -   a pump unit arranged in fluid communication with said pressure        chamber, the pump unit being configured to reciprocatingly        increase and decrease a pressure in the pressure chamber between        an increased pressure condition and a decreased pressure        condition by pumping a volume of fluid into, respectively out        of, the pressure chamber, thereby deforming the recess wall and        moving the recess wall back and forth, increasing respectively        decreasing the recess, said pump unit, in operation, operating        at an operating frequency; wherein the operating frequency is in        the range of 0.5 to 20 Hz.

The mouthpiece of the dental cleaning device according to the secondaspect of the invention of Chapter 2 is similar to the mouthpiece of thedental cleaning device according to the first aspect of the invention ofChapter 2. Additionally, the recess of said mouthpiece has a curvedlength direction, and is configured for encompassing, viewed in thecurved length direction, a substantial part of the dental arch of auser, such as substantially the entire dental arc. For example, therecess may be configured for encompassing the dental positions in therange from at least the left first molar up to at least the right firstmolar, or for encompassing the dental positions in the range from atleast the left second molar up to at least the right second molar. Allteeth or almost all teeth of a dental arch of a user may then be brushedsimultaneously with the dental cleaning device.

The dental cleaning device according to the second aspect of theinvention of Chapter 2 optionally has a plurality of bristles that aresimilar to the bristles of the dental cleaning device according to thefirst aspect of the invention of Chapter 2.

The dental cleaning device according to the second aspect of theinvention of Chapter 2 comprises a pump unit, similar to the pump unitof the dental cleaning device according to the first aspect of theinvention of Chapter 2.

According to the second aspect of the invention of Chapter 2, said pumpunit operates at a operating frequency in the range of 0.5 to 20 Hz.

In contrast to known dental cleaning devices, which operate at a ratherhigh frequency, the dental cleaning device according to the secondaspect of the invention of Chapter 2 operates at a relatively lowfrequency (compared to devices from the prior art). For example, thedental cleaning device of WO2010/076702 operates at a frequency ofbetween 100 and 300 Hz. This high-frequency movement allows thebristles, which in WO2010/076702 are made of nylon and attached to amembrane, to function as a jackhammer which jackhammer functionality isrequired for removing tooth plaque from teeth of a user of the dentalcleaning device. However, to move the bristles with such a highfrequency poses difficulties. Indeed WO2010/076702 refers to thedifficulty of overcoming the inertial of the total fluid volume, andcavitation effects in the fluid, created by the pump action.WO2010/076702 teaches how to solve these problems. It is commonly known,for a dental cleaning device operating like a jackhammer, that a highfrequency is needed (despite these known difficulties) as otherwisecleaning of the teeth takes too long and users of the dental cleaningdevice may not sufficiently clean their teeth.

The dental cleaning device according to the second aspect of theinvention of Chapter 2 takes a radically different approach compared toWO2010/076702. Instead of finding a suitable way to move the bristleswith a very high frequency, the dental cleaning device according to theinvention of Chapter 2 brushes the teeth with a rather low operatingfrequency of 0.5 to 20 Hz. It is much more energy-efficient toreciprocatingly increase and decrease the pressure in a pressure chamberwith a low operating frequency than with a high operating frequency. Asthe dental cleaning device according to the second aspect of theinvention of Chapter 2 provides a mouthpiece comprising a recess that isconfigured to encompass substantially the entire dental arch of the userand that has a U-shaped cross section, (almost) all teeth and every sideof each tooth may be brushed at the same time with the dental cleaningdevice according to the second aspect of the invention of Chapter 2.When operating the bristles at a lower frequency, instead of working asa jackhammer, the bristles may work, so to say, as a windscreen wiper,rubbing against teeth of the user as they are moved towards the teeth,and removing tooth plaque with that rubbing action. Said rubbing actioncan only effectively be performed at relatively low frequencies in therange of 0.5-20 Hz. When the movement frequency of the bristles is toohigh, there is no rubbing action but a jackhammering (chipping) action,and frequencies much higher than 20 Hz are needed. When the movementfrequency is lower than 0.5 Hz, the movement is too slow and whilerubbing may satisfactorily be performed, the total brushing time isincreased too much.

By rubbing the teeth clean of tooth plaque, at substantially all dentalpositions of a dental arch at the same time, with the dental cleaningdevice according to the second aspect of the invention of Chapter 2 ahighly efficient alternating movement of the recess wall and bristlesresults, while cleaning of the dental arch can still be performed in asatisfactory amount of time.

With the proposed dental cleaning device that operates at a relativelylow operating frequency, and brushes substantially all teeth of a dentalarch of a user at the same time by rubbing the teeth, incorrect use andineffective brushing of the teeth is made almost impossible.

Further additionally, brushing teeth with a relatively low operatingfrequency may result in a more pleasant mouth feeling when using thedental cleaning device.

In a further embodiment of the second aspect of invention of Chapter 2,said operating frequency is in the range of 1 to 15 Hz, such as in therange of 3 to 10 Hz. These operating frequency ranges provide an optimaltrade-off between on the one hand desired brushing time, and on theother hand achieved brushing result.

In another further embodiment of the second aspect of invention ofChapter 2, said operating frequency may be a predetermined frequencywhich is fixed or varies as a function of time. Like as explained inrelation to the first aspect of the invention of Chapter 2, thispredetermined frequency may for example be maintained when responding toa pressure change due to the pump being configured to operate at apredetermined operating frequency or due to a controller beingconfigured to operate the pump at a predetermined operating frequency.

In a further embodiment of the first and/or second aspect of theinvention of Chapter 2, the recess wall is made of a material that has ahardness from 20 Shore A to 100 Shore A measured according to ISO7619-1:2010. For example, the recess wall may be made of an elastomer,like a thermoplastic elastomer or a silicone elastomer A material havinga hardness of 20 to 100 Shore A, for example 50 to 80 Shore A, mayprovide an optimal trade-off between flexibility, deformability,stiffness, and durability upon continuously repeated deformation.

In an elaboration of this further embodiment, at least some of theplurality of bristles may be made of a material that has a hardness of20 to 100 Shore A. For example, the bristles may be made of anelastomer, like a thermoplastic elastomer or a silicone elastomer, or asilicon polymer. This range may provide the bristles with an optimaltrade-off between stiffness, flexibility, and deformability. On the onehand, it is desired that the bristles are relatively stiff, to increasetheir durability and to rub the teeth with sufficient force to actuallyclean them. On the other hand, it is desired that the bristles deformeasily, to rub teeth of a user of the dental cleaning device and cleansaid teeth (instead of damaging them), and to reach spots which aredifficult to reach with stiffer bristles.

In another embodiment of the first and/or second aspect of the inventionof Chapter 2, the recess wall is made of a material that has a hardnessfrom 50 Shore D to 100 Shore A measured according to ISO 7619-1:2010.For example, the recess wall may be made of a thin plastic, likepolyethylene, polybutylene terephthalate, polypropylene, polyester ornylon. A material having a hardness of 50 to 100 Shore D, for example 70to 90 Shore D, used in a thin recess wall may provide an optimaltrade-off between flexibility, deformability, stiffness, and durabilityupon continuously repeated deformation.

In an elaboration of this further embodiment, at least some of theplurality of bristles may be made of a material that has a hardness of50 to 100 Shore D. For example, the bristles may be made of plastic,like polyethylene, polybutylene terephthalate, polypropylene, polyesteror nylon. This range may provide the bristles with an optimal trade-offbetween thinner bristles with the right stiffness, flexibility, anddeformability. On the one hand, it is desired that the bristles arerelatively stiff, to increase their durability and to rub the teeth withsufficient force to actually clean them. On the other hand, it isdesired that the bristles deform easily, to rub teeth of a user of thedental cleaning device and clean said teeth (instead of damaging them),and to reach spots which are difficult to reach with stiffer bristles.

In another elaboration of this further embodiment, the bristles and therecess wall are made of the same material. Alternatively, the bristlesmay be made of a nylon material having a hardness significantly higherthan 70 Shore D, while the recess wall is made of e.g. thermoplasticelastomer or a silicone elastomer having a hardness in the range of 40to 100 Shore A.

In another further embodiment of the first and/or second aspect of theinvention of Chapter 2, the mouthpiece of the dental cleaning device hastwo said recesses, which are each U-shaped in cross section anddelimited by a said recess wall, the openings of the U-shaped crosssections of the two recesses facing in mutually opposite directions.This allows to simultaneously brush teeth and/or gum of the mandibulardental arch as well as the maxillary dental arch.

In another further embodiment of the first and/or second aspect of theinvention of Chapter 2, the one recess has or the two recesses have anelongate, curved shape and is/are configured to encompass at least 5dental positions of a user, such as the dental positions in the rangefrom the left first molar up to the right first molar. This,advantageously, allows to brush multiple dental positionssimultaneously. Satisfactory brushing of teeth can then be achieved inless time compared to a dental cleaning device having a shorter recess.The recess(es) may be configured to encompass the dental positions inthe range from the left second molar up to the right second molar. Themouthpiece may span substantially the entire dental arch of a user,including or excluding the third molars (wisdom teeth).

In another further embodiment of the first and/or second aspect of theinvention of Chapter 2, in use of the dental cleaning device, uponincreasing the pressure in the pressure chamber, the bristles of thedental cleaning device move towards the dental positions of the userwhilst end portions of said bristles are deformed (bent) rubbed againstsaid teeth; which rubbing action of said end portions cleans said teeth.Hence, in contrast to known automatic dental cleaning devices, thedental cleaning device according to the present invention of Chapter 2does not function as a jackhammer, but instead rubs the teeth, usingfriction between the bristles and the teeth as cleaning mechanism toremove tooth plaque from teeth of the user.

In an embodiment of the first and/or second aspect of the invention ofChapter 2, the fluid may be a gas, preferably air. Air is readilyavailable, and may e.g. be extracted from the environment whileoperating the dental cleaning device. Using another fluid may requirethe use of a closed-loop fluid system, which may be more expensive andcumbersome to produce. When using air as fluid, an open-loop or apartial open-loop system may be used, wherein fluid is allowed to exit,e.g. from the pressure chamber, to outside of the dental cleaningdevice.

In an embodiment of the second aspect of the invention of Chapter 2, thedental cleaning device further comprises: a pressure sensor configuredto measure a pressure representative of the pressure in the pressurechamber and to produce a pressure signal representative of the pressuremeasured, and a controller configured to generate a control signal;wherein the pressure sensor and controller are connected such that thecontroller in use receives the pressure signal and the controller andpump unit are connected such that the pump unit in use receives thecontrol signal; wherein the controller is configured to generate thecontrol signal in dependence on the pressure signal and the pump unit isconfigured to reciprocatingly provide a delivery into and/or out of thepressure chamber in response to the control signal; and wherein thecontroller is configured to reduce the delivery of the pump unit whenthe pressure in the pressure chamber exceeds a predetermined upperthreshold, as explained in accordance with the first aspect of theinvention of Chapter 2.

In an embodiment of the first and/or second aspect of the invention ofChapter 2, the recess wall may, viewed in the plane of the U-shapedcross-section transverse to the length axis—have an internalwidth—between the legs of the U-shape—in the range of 2 to 10 mm, suchas in the range of 3 to 7 mm; and/or the U-shape may have an internalheight in the range of 5 to 15 mm, such as in the range of 5 to 10 mm.These measures are indicative for an adult human. For a child or foranimals these measures might be different.

According to a third aspect of the invention of Chapter 2, there isprovided a method of operating a dental cleaning device forsimultaneously brushing at a plurality of dental positions, wherein thecleaning device comprises:

-   -   a mouthpiece having a pressure chamber and a recess delimited by        a recess wall, the recess having a curved length direction and a        U-shaped cross-section transverse to the length direction, the        recess being configured for encompassing, viewed in the curved        length direction, at least a part of the dental arch of a user,        and the pressure chamber being configured for containing a fluid        under pressure;    -   optionally, a plurality of bristles, each having one end        attached to the recess wall and extending away from the recess        wall into the; and    -   a pump unit arranged in fluid communication with said pressure        chamber, the pump unit being configured to reciprocatingly        increase and decrease a pressure in the pressure chamber between        an increased pressure condition and a decreased pressure        condition by pumping a volume of fluid into, respectively out        of, the pressure chamber, thereby deforming the recess wall and        moving the recess wall back and forth, increasing respectively        decreasing the recess,        wherein    -   the delivery of the pump unit is reduced when the pressure in        the pressure chamber exceeds a predetermined upper threshold;        and/or    -   the pump is operated at an operating frequency in the range of        0.5 to 20 Hz.        With the method according to the third aspect of the invention        of Chapter 2:    -   the pump may, when the pressure in the pressure chamber exceeds        a predetermined upper threshold, be operated such that a change        of the operating frequency is prevented;        and/or    -   the pump may be operated at a fixed operating frequency;        and/or    -   the pump may be operated at an operating frequency in the range        of 1 to 15 Hz, such as in the range of 3 to 10 Hz;        and/or    -   the upper threshold may be at most 2 bar, such as at most 1 bar,        relative to ambient pressure;        and/or    -   the upper threshold may be at most 0.3 bar, such as at most 0.2        bar, relative to ambient pressure;        and/or    -   the delivery of the pump unit may be increased when the pressure        in the pressure chamber falls below a predetermined lower        threshold, wherein:        -   the lower threshold may be in a range up to 1 bar, such as            in a range up to 0.4 bar, below the upper threshold;    -   and/or        -   the lower threshold may be in the range of −0.5 to +0.2 bar,            such as in the range of −0.5 to 0 bar, relative to ambient            pressure;            and/or    -   the pump is operated at an operating frequency which varies        according to a predetermined function of the time measured as        from switching on the pump.

BRIEF DESCRIPTION OF THE FIGURES OF CHAPTER 2

The invention of Chapter 2 will be explained further with reference tothe FIGS. 21-26. In these figures:

FIG. 21 schematically shows a part of a dental arch of a person;

FIG. 22 schematically shows an embodiment of a mouthpiece of a dentalcleaning device according to the invention of Chapter 2;

FIG. 23a schematically shows a cross-section of the mouthpiece of FIG.22, in a decreased pressure condition thereof;

FIG. 23b schematically shows a cross-section of the mouthpiece of FIG.22, in an increased pressure condition thereof;

FIG. 24 schematically shows an embodiment of a dental cleaning deviceaccording to the invention of Chapter 2;

FIG. 25 schematically shows a graph of the pressure in the pressurechamber as a function of time; and

FIG. 26 schematically shows the rubbing of teeth with bristles of adental cleaning device according to an embodiment of the invention ofChapter 2.

DETAILED DESCRIPTION OF THE FIGURES OF CHAPTER 2

FIG. 21 shows in perspective view, highly schematically a part of anupper or maxillary dental arch (jaw) 301 with dental positions 302-314.Each dental position is indicated with a vertical dashed line. Eachdental position usually comprises a tooth which is named according to anomenclature known to each dentist. Using this nomenclature:

-   -   dental position 302 is the position of the left ‘second molar’,        present in FIG. 21;    -   dental position 303 is the position of the left ‘first molar’,        missing in FIG. 21;    -   dental position 304 is the position of the left ‘second        premolar’, present in FIG. 21;    -   dental position 305 is the position of the left ‘first        premolar’, present in FIG. 21;    -   dental position 306 is the position of the left ‘canine’,        present in FIG. 21;    -   dental position 307 is the position of the left ‘lateral        incisor’, missing in FIG. 21;    -   dental position 308 is the position of the left ‘central        incisor’, present in FIG. 21;    -   dental position 309 is the position of the right ‘central        incisor’, present in FIG. 21;    -   dental position 310 is the position of the right ‘lateral        incisor’, present in FIG. 21;    -   dental position 311 is the position of the right ‘canine’,        present in FIG. 21;    -   dental position 312 is the position of the right ‘first        premolar’, present in FIG. 21;    -   dental position 313 is the position of the right ‘second        premolar’, present in FIG. 21;    -   dental position 314 is the position of the right ‘first molar’,        present in FIG. 21.

In FIG. 21 the dental position of the right ‘second molar’ is not shown,and also the dental positions of the right and left ‘third molar’, alsocalled wisdom tooth, are not shown. Similar the lower (mandibular)dental arch (jaw) has a similar number of dental positions, which are inaccordance with said nomenclature similarly named.

FIG. 21 further shows a system of three mutually orthogonal axes,comprising an x-axis X, an y-axis Y and a z-axis Z. The z-axis Z is acurved axis following the contour of the dental arch 301. The x-axis Xand y-axis Y are perpendicular to each other and define an xy-planewhich is essentially flat and perpendicular to the dental arch 301, i.e.each xy-plane intersecting a location on the z-axis is, at thatlocation, perpendicular to the curved z-axis Z. The z-axis Z defines acurved length direction. The z-axis Z and y-axis Y define a curvedzy-plane, with viewed along the z-axis, an arc-shape similar to shape ofthe dental arch. Further, the z-axis Z and x-axis X define a zx-plane.

FIG. 22 shows schematically a perspective view of an example of amouthpiece 320 or a dental cleaning device according to the first and/orsecond aspect of the invention of Chapter 2. FIGS. 23a and 23b show across section of the mouthpiece of FIG. 22, viewed as indicated byarrows XXIII in FIG. 22. In the cross section of FIG. 23a , the pressurechamber is in a relatively decreased pressure condition, while thepressure chamber is in a relatively increased pressure condition in FIG.23 b.

The mouthpiece 320 comprises a first recess 322. This first recess 322has, viewed along the z-axis of FIG. 21, a curved length direction and,viewed in the xy-plane of FIG. 21, a U-shaped cross section. The firstrecess 322 is delimited by a flexible and/or deformable recess wall 323,which is in the xy-plane U-shaped. The recess wall 323 is lined with aplurality of bristles 324, each having one end, called the root 319,attached to the flexible recess wall 323 and extending from the recesswall 323 into the first recess 322.

The recess 322 here has an elongate, curved shape and is configured toencompass substantially the entire dental arch of a user. For the dentalcleaning device according to the first aspect of the invention ofChapter 2, the recess 322 may be much shorter, e.g. spanning only asingle dental position, or at least 5 dental positions, such as in therange from the first molar on the left side of the jaw up to the firstmolar on the right side of the jaw.

Reference 326 indicates a nipple configured for connecting themouthpiece to a pumping and/or suctioning device, as will be explainedin more detail with reference to FIG. 24 in the below. The mouthpiece320 further has a right half 327 and a left half 328, which halves comeso to say together at nipple 326.

Reference 325 indicates a curved dividing line, which defines a mirrorplane parallel to the xz-plane as defined in FIG. 21. The mouthpiece asshown in FIG. 22 is so to say mirror symmetrical with respect to thismirror plane, meaning that there is a second recess (not visible in FIG.22 but visible in FIGS. 23a and 23b ) opposite the first recess 322,which second recess is lined with bristles as well. It is noted that thefirst recess may have a shape different than the shape of the secondrecess because the (teeth of the) upper and lower arch of dentalpositions generally have different shapes.

The recesses 322 are configured to encompass substantially an entiredental arch from the dental position of e.g. the right third or secondmolar to the dental position of the left third respectively secondmolar. For the first aspect of the invention of Chapter 2, the recesses322 may also be configured to encompass a part of an arch of dentalpositions, this part comprising e.g. only a single dental position.

FIGS. 23a and 23b show a cross-section according to arrows XXIII in FIG.22 of a right part of the mouth piece 320, wherein the pressure in thepressure chamber is increased in FIG. 23b (with respect to the situationof FIG. 23a ) and wherein the pressure in the pressure chamber isdecreased in the situation of FIG. 23a (with respect to the situation ofFIG. 23b ).

As can best be seen in FIGS. 23a and 23b , the bristles may be providedas tufts 329 of relatively thin bristles 324. Each tuft 329 may have abase 336 which carries the bristles 324 at their roots 319 and isattached to the flexible recess wall 323.

As can be seen in FIGS. 23a and 23b , the mouthpiece 320 has in itsupper side a first recess 322 and in its lower side a second recess 322,the upper and lower recesses 322 facing in mutual opposite directionswith respect to each other. Both recesses 322 are delimitated by aflexible recess wall 323. In cross-section parallel to the xy-plane asdefined in FIG. 21, the recess walls 323 are U-shaped and have a recesswall bottom 334 and two recess wall legs 333 extending from the recessbottom wall. The recess wall 323 is covered with tufts 329 of bristleson the legs 333 and/or bottom 334 of the recess wall.

Inside the mouthpiece there is provided a pressure chamber 335, whichmay, via the nipple 326 (FIG. 22), be filled with a fluid. The fluid maybe a gas, like air, or a liquid, like water. In the embodiment as shownin FIG. 22, the mouthpiece has one pressure chamber.

It is however noted that the mouthpiece may comprise a plurality ofpressure chambers, like 5 pressure chambers, or any other number ofpressure chambers. The not pre-published PCT/NL2018/050276 showsexamples of other numbers of pressure chambers in FIGS. 4, 5, 7, 9 and10. In case of multiple pressure chambers, all the pressure chambers orgroups of pressure chambers may according to the invention of Chapter 2be in fluid communication with each other, similar as is described inthe not pre-published PCT/NL2018/050276.

As can be seen in FIGS. 23a and 23b , the mouthpiece may comprise aninternal support structure of a material which is rigid relative to thematerial of the flexible recess wall 323. This support structure maycomprise a lingual plate 330 and a facial plate 332, both extendingalong the curved zy-plane defined in FIG. 21 and consequently, viewedalong the z-axis, having a U-shape. In order to keep the lingual plate330 and facial plate 332 at a distance from each other, the supportstructure may comprise one or more spacers 331. These one or morespacers 331 may for example be a multiple of bars or wires or a singleplate which may extend essentially parallel to the zx-plane as definedin FIG. 21. In case of a single plate as spacer, this plate may dividethe pressure chamber 335 in two pressure chambers, an upper one and alower one. These two pressure chambers may be in fluid communicationwith each other via one or more through holes through the plate. In caseof large through holes and/or a large number of through holes the twopressure chambers may effectively be one single pressure chamber.

The mouthpiece as shown in FIG. 22 is configured for simultaneouslybrushing at a plurality of dental positions. In case a tooth is present,the tooth of the respective dental position will be brushed. Theremnants at a dental position, like the gum, may be brushed in case atooth may be missing and the teeth adjacent the location of the missingtooth may be additionally brushed by bristles intended for the locationof the missing tooth.

The single pressure chamber 335 comprises a first flexible recess wall323 delimiting the first recess 322 (the upper one in FIGS. 23a and 23b) and a second flexible recess wall 323 delimiting the second recess 322(the lower one of FIGS. 23a and 23b ). The first and second recess walls323 are deformable, in particular by increasing or decreasing thepressure in the pressure chamber 323. The flexible recess walls 323 maybe made from an elastic material, such as a rubberlike material. Theflexible recess walls 323 may also be made from a non-elastic material.The material of the flexible recess walls 323 may keep a predeterminedshape when there is substantially no, or a low, pressure differenceacross an inner side and an outer side of the flexible recess walls 323(when the pressure in the pressure chamber substantially equals theambient pressure.

The mouthpiece 400 is configured for the tufts 329 or bristles 324 toengage the tooth surface of teeth of a dental arch or, in case one ormore dental positions the tooth might be missing, to engage the gum atthe respective dental position(s) at least when the pressure in thepressure chamber 335 is increased. In case a tooth might be missing at adental position, especially the tufts 329 of bristles at the free endsof the recess wall legs 333 will engage the gum at the empty dentalposition.

Viewed in length direction Z of the dental arch—as defined in FIG. 21 —,the tufts 329 of bristles 324 may be arranged at about the same densityas viewed in the cross-sections shown in FIGS. 23a and 23 b.

With reference to FIGS. 23a and 23b , when the pressure in the pressurechamber 335 is increased to an increased pressure condition, for exampleby feeding a fluid to the pressure chamber 335, or increasing an amountof fluid in the pressure chamber 335, the recess walls 323 are so to saycompacted to narrow the recess 322, whereby the bristles 324, inparticular the free ends thereof, may engage tooth surfaces firmlyand/or may be deformed against tooth surfaces; the situation of FIG. 23b(wherein a tooth is not shown). When the pressure in the pressurechamber 335 is decreased subsequently, the recess walls are so to saywidened to enlarge the recess 322; the situation of FIG. 23a (wherein,again, a tooth is not shown). This narrowing and widening of the recesswalls may be small, but when alternatingly repeated with some frequencyof for example 0.5-20 Hz, this alternatingly deforming of the recesswall by alternatingly narrowing and widening it, causes the bristles tomove between a firmer and relatively less firm engagement with toothsurfaces and/or the bristles to alternate between a first and seconddeformed condition, which in turn causes a sweeping and/or rubbing ofbristles along the tooth surfaces.

By a suitable cycle of increasing and decreasing pressure in thepressure chamber 335 an effective brushing action of the mouthpiece canbe obtained. The bristles 324 attached to the recess wall bottom 334generally perform an upward and downward motion during such cycling, andthe bristles 324 at the recess wall legs 333 generally perform asideways motion to and fro teeth of the user during such cycling in thedirection of the x-axis as defined in FIG. 21.

Just by way of example to give some indication of dimensions andreferring to FIG. 21, for an adult human the width of a teeth element inthe X direction varies, depending on the dental position between about 2to 12 mm. Taking into account that it is desired to keep the mouthpieceas small as possible, the internal width of the U-shape of the recesswall in the X direction is to be kept as small as possible and may beabout 0 to 4 mm wider than the width of the respective tooth. By way ofexample to give some indication of dimensions, the internal width of theU-shape of the recess wall may, viewed in the X-direction of FIG. 21, bein the range of 0 to 20 mm, such as in the range of 2-12 mm. Thebristles may be up to 6 mm long. In case for example the bristles are 3to 4 mm long, this means that between the bristles extending fromopposing recess wall legs 333 no interspace or a limited amount ofinterspace of about 2-4 mm is left. In FIG. 23, these interspaces areshown exaggerated. Further by way of example to give some indication ofdimensions, the U-shape of the recess wall may have, viewed in theY-direction of FIG. 21, an internal height in the range of 3 to 20 mm,such as in the range of 5 to 10 mm. These internal width and internalheight measures are indicative for an adult human. For a child or foranimals these measures might be different.

Increasing and decreasing the pressure in the pressure chamber 335 iseffected by a pump unit. Different pump unit and valve combinations arepossible. One possible embodiment is explained now with reference toFIG. 24. FIG. 24 schematically depicts, in a partially cut-awayperspective view, a dental cleaning device 500 comprising a handlemember 502 and a mouthpiece 400 coupled thereto, e.g. a mouthpiece asdescribed in the above. The handle member 502 is provided with a handleinterface, and the mouthpiece 400 is provided with a mouthpieceinterface configured to be detachably coupled to the handle interface.The handle member 500 comprises a battery 510 for storing electricalenergy which can be fed to the battery 510 through a battery charginginterface 512. The battery 510 provides energy to a printed circuitboard, PCB, 514, to a main pump unit 504 comprising a motor 516, atransmission 518, a crank piston 520 and a piston pump 522, and tooptionally a mouthwash pump 524. A mouthwash capsule 530 containing amouthwash liquid may be removably accommodated in the handle member 500.The piston pump 522 may be a pneumatic pump. Instead of a piston pumpalso a diaphragm pump, a plunger pump, a membrane pump, or bellows pumpmay be used. The mouthwash pump 524 may be a hydraulic pump.

The dental cleaning device 400 further comprises a pressure sensor 540,here very schematically illustrated and positioned near duct 542. Thepressure sensor 540 is configured to measure a pressure representativeof the pressure in the pressure chamber and to produce a pressure signalrepresentative of said pressure. Hence, from the pressure of the fluidat the entrance of the duct 542, the pressure sensor 540 is able toestimate or determine the pressure in the pressure chamber. The pressuresensor 540 is able to communicate with a controller 524, here integratedwith PCB 514, such that the controller 524 can receive a pressure signalfrom the pressure sensor 540.

As already said, the dental cleaning device 400 further comprises acontroller 524, here integrated with PCB 514. The controller 524 isconfigured to generate a control signal, in dependence on the pressuresignal it receives from the pressure sensor 540. The controller 524 isable to communicate with pump unit 504, such that the pump unit 504receives the control signal from the controller 524. In response to thecontrol signal received from the controller 524, the pump unit 504provides a delivery (in litres per minute) into and/or out of thepressure chamber, which delivery increases and decreases the pressure inthe pressure chamber. When the control signal indicates that thepressure in the pressure chamber exceeds a pre-determined upperthreshold value, the delivery of the pump unit 504 is reduced, to allowthe pressure in the pressure chamber to decrease again, and fall belowthe threshold value.

The operation of the dental cleaning device 500 is thus controlled bythe PCB 214, which includes a controller 524. The PCB 214 controls theoperation of the pump unit 504, including motor 516. The PCB 514controls the dental cleaning device 500 to alternatingly increasing anddecreasing the pressure in at least one pressure chamber provided in themouthpiece 504, by controlling the delivery of the fluid into and out ofthe pressure chamber by the pump unit 504.

This controlling of the pressure in the pressure chamber, by providing adelivery, is explained more graphically with reference to FIG. 25.Visible in FIG. 25 is a sinusoidal line that may represent the pressurein the pressure chamber fluctuating due to reciprocatingly beingincreased and decreased. Indicated by horizontal lines are the upperthreshold TU and the lower threshold TL. The upper threshold TU may e.g.be at most 2 bar relative to the ambient pressure, such as at most 1bar, at most 0.3 bar, or at most 0.2 bar above the ambient pressure. Thelower threshold TU may e.g. be up to −1 bar relative to the upperthreshold TU, such as up to −0.4 bar relative to the upper threshold TU.Relative to the ambient pressure, the lower threshold TL may be in therange of −0.5 bar up to +0.2 bar, e.g. up to 0 bar. When the pressureexceeds the upper threshold TU, according to the invention of Chapter 2,the delivery of the pump is reduced. When the pressure drops below thelower threshold TL, the delivery of the pump may be increased.

Starting on the left of FIG. 25, at timestamp to, fluid is being pumpedin the pressure chamber, increasing the pressure therein. Approximatelytwo normal pressurization cycles are shown, in which the pressure is inbetween the upper threshold TU and the lower threshold TL. The pumpoperates at a frequency f, which frequency f can be derived from thetime between two consecutive pressure peaks (upon normal operation ofthe pump). The normal amount of delivery D1 represents the amount offluid pumped into the pressure chamber between a lower pressure peak andan upper pressure peak (upon normal operation of the pump). Depending one.g. the fit of the dental cleaning device with respect to a (portionof) a dental arch of a user and the bite pressure exerted by a user, thepressure remains in between the upper threshold TU and the lowerthreshold TL at all times. Indeed, this scenario is shown for the firsttwo pressurization cycles. The exact pressure with respect to the upperTU and lower TL threshold may however vary per individual user, as isindicated by arrows B.

At timestamp t₁, the pressure in the pressure chamber suddenly increasesrapidly. This may e.g. be caused by a movement of the dental cleaningdevice from a position near the incisor teeth (which are typicallyrelatively narrow) towards a position near the molars (which aretypically relatively broad). A broader tooth between the recess reducesthe size of the pressure chamber, and increases the pressure therein.Alternatively, such a sudden increase in pressure may e.g. be caused dueto the increase of the bite pressure of the user, and/or an increase inthe force with which the dental cleaning device is pressed onto theteeth by the user.

A little while later, the dental cleaning device responds to thisincrease in pressure, by reducing the delivery D2 of the pump. In thepresent example, the reduction in delivery is sufficient to bring thepressure immediately below the upper threshold TU (within onepressurization cycle), but it is conceived that this takes more thanone, e.g. two, three, or four pressurization cycles. It is further notedthat the response of the pump unit here lags somewhat behind theoccurrence of the increased pressure.

After reducing the delivery D2 once, achieving the desired effect ofreducing the pressure below the upper threshold TU, normal operation isagain continued, with the same delivery D1 as before timestamp t₁.

In the example of FIG. 25, at timestamp t₂, a sharp drop of the pressurein the pressure chamber is observed. This may e.g. occur when the dentalcleaning device is moved from a position near the molars towards aposition near the incisor teeth, and/or when the application pressureexerted by the user is reduced, and/or when the bite pressure applied bythe user is reduced.

The dental cleaning device responds to this decrease in pressure byincreasing the delivery D3 of the pump. In the present example, theincrease in delivery is insufficient to immediately bring the pressuresufficiently above the lower threshold TL. Therefore, the increaseddelivery D3 is maintained, until the pressure in the pressure chamber isat a sufficient level again. In the present example, the response of thepump unit here lags somewhat behind the occurrence of the decreasedpressure, responding only when the pressure has significantly droppedbelow the lower threshold TL. It is conceived that reaction is faster,responding already when a sharp drop in pressure is noticed, maybe evenbefore the lower threshold is reached.

In the embodiment of FIG. 25, the pressure is increased until the lowestpressure experienced in the pressurization cycles is above the lowerthreshold TL. Possibly, the pressure is increased only to the levelwherein the maximum pressure during the pressurization cycle is betweenthe upper TU and lower TL threshold. In that case, only one increaseddelivery D3 might be needed.

It is noted that, as preferred, the operation frequency of the pump unitdoes not change when the delivery alters. The operation frequency of thepump unit remains at a predetermined frequency, which may be in therange of 0.5 to 20 Hz and which may be a fixed value or may vary as afunction of time.

FIG. 26 highly schematically shows how, after increasing the pressure inthe pressure chamber, the wall 533 and bristles of the dental cleaningdevice are moved in the direction of teeth of the user. The end portionsof the bristles are deformed and rub against the teeth, which rubbingaction cleans the teeth of tooth plaque.

The next following clauses 40-64 give examples of the above describedinventions of Chapter 2 and further aspects and embodiments of theseinventions of Chapter 2:

-   -   40] A dental cleaning device for simultaneously brushing at a        plurality of dental positions, comprising:        -   a mouthpiece having a pressure chamber and a recess which is            U-shaped in cross section and delimited by a flexible and/or            deformable recess wall, the pressure chamber being            configured for containing a fluid under pressure,        -   optionally, a plurality of bristles, each attached to the            recess wall with one end thereof and extending from said            recess wall into the recess;        -   a pump unit arranged in fluid communication with said            pressure chamber, the pump unit being configured to            reciprocatingly increase and decrease a pressure in the            pressure chamber between an increased pressure condition and            a decreased pressure condition by pumping a volume of fluid            into, respectively out of, the pressure chamber, thereby            deforming the recess wall and moving the recess wall back            and forth increasing respectively decreasing the recess,    -   wherein the dental cleaning device further comprises:        -   a pressure sensor configured to measure a pressure            representative of the pressure in the pressure chamber and            to produce a pressure signal representative of said            pressure, and        -   a controller configured to generate a control signal;    -   wherein the pressure sensor and the controller are connected        such that the controller, in use, receives the pressure signal        from the pressure sensor and the controller and pump unit are        connected such that the pump unit, in use, receives the control        signal from the controller;    -   wherein the controller is configured to generate the control        signal in dependence on the pressure signal and the pump unit is        configured to provide a delivery into and/or out of the pressure        chamber in response to the control signal; and wherein the        controller is configured to reduce the delivery of the pump unit        when the pressure in the pressure chamber exceeds a        predetermined upper threshold.    -   41] Dental cleaning device according to clause 40, wherein the        pump unit has an operating frequency, and wherein the        configuring of the controller, to reduce the delivery of the        pump unit when the pressure in the pressure chamber exceeds a        predetermined upper threshold, is such that a change of the        operating frequency is prevented.    -   42] Dental cleaning device according to clause 40 or 41, wherein        the pump unit has an operating frequency, and wherein:        -   the controller is configured to operate the pump unit in            response to a pressure change at a predetermined operating            frequency    -   or        -   the pump unit is configured to operate at a predetermined            operating frequency.    -   43] Dental cleaning device according to one of clauses 40-42,        wherein the pump unit has an operating frequency which varies        according to a predetermined function of the time measured as        from switching on the pump unit.    -   44] Dental cleaning device according to one of the clauses        40-42, wherein the pump unit has an operating frequency which is        a fixed predetermined value.    -   45] Dental cleaning device according to one of the clauses        40-44, wherein said operating frequency is in the range of 0.5        to 20 Hz.    -   46] Dental cleaning device according to one of the clauses        40-45, wherein said upper threshold is at most 2 bar relative to        ambient pressure, such as at most 1 bar relative to ambient        pressure.    -   47] Dental cleaning device according to one of the clauses        40-46, wherein said upper threshold is at most 0.3 bar relative        to ambient pressure, such as at most 0.2 bar relative to ambient        pressure.    -   48] Dental cleaning device according to one of the clauses        40-47, wherein the controller is further configured to increase        the delivery of the pump unit when the pressure in the pressure        chamber falls below a predetermined lower threshold.    -   49] Dental cleaning device according to clause 48, wherein said        lower threshold is in a range up to 1 bar, such as in a range up        to 0.4 bar below the upper threshold.    -   50] Dental cleaning device according to clause 48 or 49, wherein        said lower threshold is in the range of −0.5 to +0.2 bar        relative to ambient pressure, such as in the range of −0.5 to 0        bar relative to ambient pressure.    -   51] A dental cleaning device for simultaneously brushing at a        plurality of dental positions, comprising:        -   a mouthpiece having a pressure chamber and a recess            delimited by a recess wall, the recess wall having a curved            length direction and a U-shaped cross-section transverse to            the length direction, the recess wall being configured for            encompassing, viewed in the curved length direction, the            dental positions in the range from at least the left second            pre-molar to at least the right second premolar, and the            pressure chamber being configured for containing a fluid            under pressure;        -   optionally, a plurality of bristles, each having one end            attached to the recess wall and extending away from the            recess wall into the recess; and        -   a pump unit arranged in fluid communication with said            pressure chamber, the pump unit being configured to            reciprocatingly increase and decrease a pressure in the            pressure chamber between an increased pressure condition and            a decreased pressure condition by pumping a volume of fluid            into, respectively out of, the pressure chamber, thereby            deforming the recess wall and moving the recess wall back            and forth, increasing respectively decreasing the recess,            said pump unit, in operation, operating at a predetermined            operating frequency;    -   wherein the predetermined operating frequency is in the range of        0.5 to 20 Hz.    -   52] Dental cleaning device according to clause 51, wherein the        predetermined operating frequency is in the range of 1 to 15 Hz,        such as in the range of 3 to 10 Hz.    -   53] Dental cleaning device according to clause 51 or 52, wherein        the predetermined operating frequency is a fixed frequency.    -   54] Dental cleaning device according to clause 51 or 52, wherein        the predetermined operating frequency varies according to a        predetermined function of the time measured as from switching on        the pump unit.    -   55] Dental cleaning device according to one of the clauses        40-54, wherein, in use, upon increasing the pressure in the        pressure chamber, the bristles move towards the dental positions        of the user whilst end portions of said bristles are deformed        and rubbed against said teeth, which rubbing action of said end        portions cleans said teeth.    -   56] Dental cleaning device according to one of the clauses        40-55, wherein the recess wall of the recess and/or at least        some of the bristles is (are) made of a material that has a        hardness of 20-100 Shore A, such as 50-80 Shore A.    -   57] Dental cleaning device according to one of the clauses        40-55, wherein the recess wall of the recess and/or at least        some of the bristles is (are) made of a material that has a        hardness of 50-100 Shore D, such as 70-90 Shore D.    -   58] Dental cleaning device according to one of the clauses        40-57, wherein the mouthpiece has two said recesses, which are        each U-shaped in cross section and delimited by a said recess        wall, the openings of the U-shaped cross sections of the two        recesses facing in mutually opposite directions.    -   59] Dental cleaning device according to one of the clauses        40-58, wherein the recess or the two recesses has, respectively        have an elongate, curved shape and is/are configured to        encompass at least 5 dental positions of a user, such as the        dental positions in the range from the left first molar up to        the right first molar.    -   60] Dental cleaning device according to one of the clauses        40-59, wherein the pump unit comprises a pump chosen from the        following group: a piston pump, a diaphragm pump, a plunger        pump, a membrane pump, or a bellows pump.    -   61] Dental cleaning device according to one of the clauses        15-60, wherein the dental cleaning device further comprises:        -   a pressure sensor configured to measure a pressure            representative of the pressure in the pressure chamber and            to produce a pressure signal representative of said            pressure, and        -   a controller configured to generate a control signal;    -   wherein the pressure sensor and the controller are connected        such that the controller in use receives the pressure signal        from the pressure sensor and the controller and pump unit are        connected such that the pump unit in use receives the control        signal from the controller;    -   wherein the controller is configured to generate the control        signal in dependence on the pressure signal and the pump unit is        configured to provide a delivery into and/or out of the pressure        chamber in response to the control signal; and wherein the        controller is configured to reduce the delivery of the pump unit        when the pressure in the pressure chamber exceeds a        predetermined upper threshold.    -   62] Dental cleaning device according to clause 58 in combination        with one of the clauses 46-50.    -   63] Method of operating a dental cleaning device for        simultaneously brushing at a plurality of dental positions,        wherein the cleaning device comprises:        -   a mouthpiece having a pressure chamber and a recess            delimited by a recess wall, the recess wall having a curved            length direction and a U-shaped cross-section transverse to            the length direction, the recess wall being configured for            encompassing, viewed in the curved length direction, at            least a part of the dental arch of a user, and the pressure            chamber being configured for containing a fluid under            pressure;        -   optionally, a plurality of bristles, each having one end            attached to the recess wall and extending away from the            recess wall into the recess; and        -   a pump unit arranged in fluid communication with said            pressure chamber, the pump unit being configured to            reciprocatingly increase and decrease a pressure in the            pressure chamber between an increased pressure condition and            a decreased pressure condition by pumping a volume of fluid            into, respectively out of, the pressure chamber, thereby            deforming the recess wall and moving the recess wall back            and forth, increasing respectively decreasing the recess,    -   wherein        -   the delivery of the pump unit is reduced when the pressure            in the pressure chamber exceeds a predetermined upper            threshold;    -   and/or        -   the pump unit is operated at an operating frequency in the            range of 0.5 to 20 Hz.    -   64] Method according to clause 63, wherein:        -   when the pressure in the pressure chamber exceeds a            predetermined upper threshold the pump unit is operated such            that a change of the operating frequency is prevented;    -   and/or        -   the pump unit is operated at a fixed operating frequency;    -   and/or        -   the pump unit is operated at an operating frequency in the            range of 1 to 15 Hz, such as in the range of 3 to 10 Hz;    -   and/or        -   the upper threshold is at most 2 bar, such as at most 1 bar,            relative to ambient pressure;    -   and/or        -   the upper threshold is at most 0.3 bar, such as at most 0.2            bar, relative to ambient pressure;    -   and/or        -   the delivery of the pump unit is increased when the pressure            in the pressure chamber falls below a predetermined lower            threshold, wherein:            -   the lower threshold is in a range up to 1 bar, such as                in a range up to 0.4 bar, below the upper threshold;        -   and/or            -   the lower threshold is in the range of −0.5 to +0.2 bar,                such as in the range of −0.5 to 0 bar, relative to                ambient pressure;    -   and/or        -   the pump unit is operated at an operating frequency which            varies according to a predetermined function of the time            measured as from switching on the pump unit.

As follows from the above the term ‘pressure chamber’ as used throughoutthis Chapter 2 is a chamber in which the pressure is changed between adecreased pressure condition and an increased pressure condition. Thedecreased pressure condition and increased pressure condition may bothbe a pressure below ambient pressure, i.e. a vacuum defined as apressure between 0 and 1 bar. Alternatively, the decreased pressurecondition and increased pressure condition may both be a pressure aboveambient pressure, or one of these pressure conditions may be aboutambient pressure whilst the other is below or above ambient pressure.

Where in this Chapter 2 the terminology ‘pressure in the pressurechamber’ or similar terminology is used, it is the ‘pressure of thefluid in the pressure chamber’. It is the pressure of the fluid whichacts on the recess wall to cause the brushing action. The pressure ofthe fluid may for example be increased by supplying additional fluidinto the pressure chamber or decreased by allowing fluid to leave thepressure chamber.

Taking into account the shape of the various dental positions/naturalteeth, the shape of the U-shaped cross section may vary along the lengthdirection of the recess/recess wall. In the region of the upper and orlower incisors, the U-shaped cross section may for example be V-shaped.

CHAPTER 3

Title: Mouthpiece for brushing at a plurality of dental positions,brushing device comprising such mouthpiece, and method of operating sucha mouthpiece or brushing device.

The invention of Chapter 3 relates to the field of dental cleaningdevices, in particular to a mouthpiece for simultaneously brushing at aplurality of dental position. The invention of Chapter 3 further relatesto a brushing device comprising the mouthpiece according to theinvention of Chapter 3. The invention of Chapter 3 furthermore relatesto a method of operating such a mouthpiece or brushing device. Themouthpiece is configured to brush at at least 5 dental positions at thesame time.

BACKGROUND OF THE INVENTION OF CHAPTER 3

Cleaning of teeth of humans and animals is a prerequisite for oralhealth, and health of internal organs. Various dental cleaning devicesare available, such as manual and powered toothbrushes. With thesetypical toothbrushes, it is advised to brush the teeth by a prescribedmethod for at least two minutes per day to effectively remove plaque.Yet, an average person does not spend all of the prescribed timecleaning his or her teeth, and does not always brush according to aneffective method. Additionally, for disabled or elderly persons orchildren it can be difficult to brush the teeth with a toothbrush, sincetypical toothbrushes require precise positioning of the brush bristleson various surfaces of the teeth. Additionally, persons may exert toomuch pressure on brush bristles during brushing the teeth, whereby notonly the bristles wear rapidly and excessively, but also the brushingprocess is not effective, teeth may be damaged, and tooth gum maywithdraw which has adverse consequences for the dental health.

In case at some or all dental positions teeth are missing as isfrequently the case with elderly persons, cleaning of the gum at thesedental positions is still a prerequisite for oral health, and health ofinternal organs.

There is a need to automatically brush the teeth and/or gum at thedental positions for cleaning the teeth and/or gum at these dentalpositions, whereby the time and effort required for effective brushingis reduced. In addition, there is a need to avoid carefully manoeuvringthe brush.

Dental cleaning devices are known comprising mouthpieces which coverboth the maxillary dental arch and the mandibular dental arch. Such amouthpiece comprises brushing surfaces with bristles, which areautomatically moved, to clean the complete set of teeth.

The mouthpiece and the brushing surfaces of the known dental cleaningdevices require adjustment to fit closely to the shape of a user'sdental arch. The mouthpiece should be able to clean every tooth surface.However, dental arches vary greatly among different users due to varyingsizes of the dental arch, malocclusion, missing teeth, and the like. So,there is a need for a dental cleaning device with an adjustablemouthpiece.

Reference US 2010/0062397 A1 discloses an electric dental cleaningdevice with a mouthpiece. This known mouthpiece has an upper part forcleaning the maxillary/upper arch of the teeth and a lower part forcleaning the mandibular/lower arch of the teeth. Both the upper part andthe lower part of this know mouthpiece each have a brush pad, whichbrush pads each have a U-shaped cross section and bristles on the insideof the U-shape. These two brush pads are positioned with the bottoms ofthe U-shape of the pads facing towards each other and the legs of theU-shape of the upper brush pad pointing in an upward direction oppositeto the legs of the U-shape of the lower brush pad, which point indownward direction. The brush-pads comprise rigid brush plates on theoutside of the U-shape, a leg plate at each leg and a bottom platetransverse to the leg plates at the bottom of each U-shape. TheseU-shaped brush pads are driven up and down relative to the freeends/tops of the teeth in the direction of the legs of the U shape. Insome embodiments, a bladder may be positioned between the maxillary archand mandibular arch of the mouthpiece, i.e. between the bottom plates,and alternating or oscillating pneumatic pressure and suction may beapplied to this bladder to move the bottom plates relative to eachother, which in turn causes an up and down movement of the U-shapedbrush pads, thereby brushing the teeth.

In one embodiment of the mouthpiece according to the reference US2010/0062397 A1, the mouthpiece is adjustable in that the side/leg brushplates are positioned against the lingual and facial side of teeth bythe use of flexible fingers and/or bladders which are configured toexert a static pressure to cause the tips of the bristles of the brushplates to engage the lingual and facial side of the teeth whilst movingup and down, transverse to the direction of the static pressure, alongthe lingual and facial side of the teeth in a direction.

In US 2010/0062397 A1 the brushing movement is only a 1-D-movement (onedimensional movement) as the U-shaped brush pads are only moved towardsand away from each other.

The mouthpiece according to US 2010/0062397 A1 has a drawback of alimited brushing action, since the bristles on the brush pads have alimited capability to reach all surfaces of the teeth since they aremounted on rigid plates.

Reference U.S. Pat. No. 4,795,347—which has as corresponding Europeanapplication, EP-A-0173114—discloses several embodiments of devices forcleaning a tooth, which can be divided in two types of devices eachintended for encompassing one tooth at a time for, so to say, cleaningone tooth at a time. The device of the first type ensures a staticbrushing pressure of the bristles on the tooth whilst the brushingmovement of the bristles is caused by hand, i.e. the brush head ismounted on a handgrip which is manipulated to move the brush head like aregular tooth brush along the tooth. In this first type one singlepressure chamber or two opposing pressure bubbles may be used to ensurethat the cleaning contact pressure between the individual bristle tuftsand the tooth is at least approximately equal all over.

Whilst in the first type the brushing movement of the tufts is to becaused by hand, the brushing movement of the device according to thesecond type is automated by a drive. The device of the second type,shown in FIGS. 10-21 of U.S. Pat. No. 4,795,347, is designed so that thetufts are driven to perform a 2-D-movement (two dimensional movement)with respect to the tooth surface. Each tuft is driven to move in aplane perpendicular to the dental arch, i.e. to the tooth cleaned. In afirst stage the tufts are moved towards the tooth to press against thetooth, subsequently the tufts are moved along the tooth surface in adirection from the gum in tooth-axial direction towards the top/crown ofthe tooth, followed by moving the tufts away from the tooth to lower thepressure and moving the tufts back from the top/crown towards the gum ofthe tooth for starting the next cycle. In this second type pressurebubbles may be used to drive the tufts to perform this 2-D-movement. Inthese embodiments the tufts are mounted on a rigid cleaning elementcarriers onto which the pressure bubbles act directly or indirectly viarocker arms.

The automated mouthpiece according to U.S. Pat. No. 4,795,347 A1 has asdrawback a limited brushing action, since the tufts have a limitedcapability to reach all surfaces of the tooth since they are mounted onrigid carriers. A further disadvantage of this mouthpiece is that onlyone tooth at a time is cleaned in automated manner and that for cleaningall teeth the automated mouthpiece of U.S. Pat. No. 4,795,347 has to bemoved manually along all teeth, which is time consuming.

Thus there remains a need for an automatic dental cleaning device whichis fast and thorough in cleaning multiple teeth simultaneously. Also, aneed remains for an automatic dental cleaning device which requires aslittle effort from the user as possible. Also, a need remains for anautomatic dental cleaning device which effectively reaches substantiallyall tooth surfaces.

Further reference is made to PCT/NL2018/050276 filed on 27 Apr. 2018 byapplicant. This application PCT/NL2018/050276 was not yet published atthe priority dates of the present application, i.e. thisPCT/NL2018/050276 is not pre-published. The mouthpiece according to thisearlier application of applicant is capable of brushing all teeth of theupper and lower dental arch in one go and has at least one pressurechamber comprising a flexible wall part provided with the bristles. Theflexible wall part is configured to be deformable by alternatinglyincreasing pressure and decreasing pressure of a fluid in the pressurechamber.

SUMMARY OF THE INVENTION OF CHAPTER 3

It is an object of the invention of Chapter 3 to provide an alternativemouthpiece for brushing at a plurality of dental positions, inparticular an automatic brushing device. A further object of theinvention of Chapter 3 is to provide an improved mouthpiece for brushingat a plurality of dental positions and to provide a brushing deviceprovided with the improved mouthpiece. Another further object isproviding a mouthpiece for brushing at a plurality of dental positionsand a brushing device comprising such a mouthpiece, which overcome oneor more of the disadvantages of brushing mouthpieces respectivelybrushing devices known from the prior art. More specifically, theinvention of Chapter 3 has as an object to provide a mouthpiece, likethe one of the not pre-published PCT/NL2018/050276 from applicant or US2010/0062397, with improved brushing action.

According to a first aspect of the invention of Chapter 3, one or moreof the above objects are achieved by providing a mouthpiece according toclaim 65, having a preamble known from the not pre-publishedPCT/NL2018/050276.

According to the invention of Chapter 3 a mouthpiece is provided forsimultaneously brushing at a plurality of dental positions. In otherwords a mouthpiece is provided which is configured for brushing at aplurality of dental positions at the same time. In case a natural orartificial tooth element is present at the dental position where themouthpiece brushes, this tooth element is brushed. In case a toothelement is absent at the dental position where the mouthpiece brushes,the gum may be brushed.

The mouthpieces according to the invention of Chapter 3 comprises a bodyprovided with at least one recess, which may be one or two recesses.This at least one recess has a curved length direction and a U-shapedcross-section transverse to the length direction and is configured forencompassing, viewed in the curved length direction, a plurality of atleast 5 dental positions. The body comprises, per said recess, aflexible recess wall delimiting the respective recess. The recess wallmay be a sheet, which may for example be made of a plastic, likepolyethylene, polypropylene, polyester or nylon, or an elastomer, like athermoplastic elastomer or a silicone elastomer. The recess wall may belined with a plurality of bristles, each having one end attached to therecess wall and extending from the recess wall into the recess. In otherwords, the body has a recess, the wall of which may be covered withbristles distributed over the wall of the recess. At least five dentalpositions, like the tooth elements of these positions or the gumcovering the jawbone at the location of the dental position, can bereceived in the recess, and, in case present, the bristles in the recesswill be able to brush the at least 5 dental positions at the same time.The bristles may be of a nylon, an elastomer or any other suitablematerial. In case of a dental arch without teeth, the remaining arch ofgum may need treatment as well. In this case the gum may be massaged bya recess wall without bristles. For improved cleaning of the gum, acleaning fluid may be used in such a mouthpiece without bristles.

The body is according to the invention of Chapter 3 provided with atleast one pressure chamber configured for containing a fluid underpressure, which pressure can be increased and decreased. The body isconfigured to deform the recess wall by reciprocatingly increasing anddecreasing the pressure in the at least one pressure chamber causing asustained repeating, reciprocating motion of the recess wall andbristles, optionally provided on that recess wall. The body thuscomprises one, two, three, four, five, six or any other number ofpressure chambers which can be filled with a fluid, as explained inPCT/NL2018/050276, which is in the name of the same applicant and wasnot yet published at the priority dates of the present application. Byreciprocatingly increasing a pressure in the at least one of thepressure chambers from a decreased pressure condition to an increasedpressure condition and decreasing the pressure in this pressurechamber(s) from the increased pressure condition to the decreasedpressure condition and sustained repeating this reciprocating motion,the recess wall, optionally carrying bristles, is brought into motionresulting in the recess wall respectively the bristles acting at thedental positions on the objects—teeth and/or gum present at these dentalpositions—to clean said objects.

With respect to the terminology increased pressure condition and‘decreased pressure condition’ it is noted that these conditions are inrelation to each other, i.e. in decreased pressure condition thepressure is lower than in increased pressure condition. In bothconditions, the pressure may for example be lower than ambient airpressure.

Ambient air pressure is the pressure prevailing in the room where theuser of the mouthpiece is when using the mouthpiece. In general ambientair pressure is assumed to be about 1 bar absolute pressure, but theactual value of the ambient air pressure will depend amongst others fromthe height with respect to sea level and weather conditions.

According to the invention of Chapter 3 the recess wall is configured tobe locally deformable such that—or, in other words, to have such a localdeformability that—when reciprocatingly increasing and decreasing thepressure in the pressure chambers or one or more one said at least onepressure chamber (‘in the pressure chambers or one or more said at leastone pressure chamber’ will further be named ‘in a said at least onepressure chamber’), the shape of the recess wall locally changes,wherein, in the increased pressure condition, the bristles (or—inabsence of bristles—the recess wall) are pressed against the dentalpositions and the shape of the recess wall is locally adjusted to thelocal shape of the dental positions encompassed by the recess wallwhilst, in the decreased pressure condition, the shape of the recesswall is locally less adjusted to the local shape of the dental positionsencompassed by the recess wall than in the increased pressure condition.So the recess wall may—thinking away the bristles—initially have asmooth surface, which, when increasing pressure, changes into a bumpysurface due to the locally deformable recess wall being pressed so tosay against—again thinking away the bristles which are in between—theirregular contour of the dental positions. The recess wall thus islocally adjusted to the shape of the dental position(s) at thatlocation. This adjusted shape in the increased pressure condition may bea mating adjustment, in which the shape of the recess wall is so to sayidentical to the contour of the dental positions, but this does not haveto be the case and in practise may not be the case. When decreasingpressure, the recess wall will return in the direction of its initialstate and assume a shape which is locally less adjusted—relative to theadjusted shape in the increased pressure condition —. This locally lessadjusted shape may still be adjusted in some extent to the local shapeof the dental contour, but the adjustment will be less pronounced. Thischange in shape of the recess wall between a locally adjusted shape anda locally less adjusted shape, results in that the bristles can betterreach into interdental spaces, and results in an additional movement ofthe bristles on top of the movement already caused by increasing anddecreasing the pressure in the at least one pressure chamber. Thisadditional movement results in additional sweeping effect of thebristles. Summarizing the change in shape of the recess wall between alocally adjusted shape and a locally less adjusted shape results inimproved brushing action.

According to a further embodiment of the first aspect of the inventionof Chapter 3, the recess wall may, viewed in the length direction alonga lingual and facial side of the dental positions encompassed by therecess wall, have in the decreased pressure condition less relief thanin the increased pressure condition.

According to a further embodiment of the first aspect of the inventionof Chapter 3, the local deformability of the recess wall may beconfigured such that the local changes in the shape of the recess wall,between the increased pressure and decreased pressure condition, occurat a pressure difference in a range up to 2 bar, such as in a range ofup to 0.4 bar, the pressure difference being defined as the pressure inthe pressure chamber in the increased pressure condition minus thepressure in the pressure chamber in the decreased pressure condition.With the expression ‘a pressure difference in a range up to x bar’, ismeant a pressure difference as from zero (not including zero) up to xbar (including x bar). Keeping the pressure difference between theincreased pressure condition and decreased pressure condition below 2bar, prevents the user from experiencing an unbearable pressuredifference. Keeping the pressure difference below 0.4 bar results inthat the pressure difference between increased pressure condition anddecreased pressure condition is, in general, experienced by a user asacceptable. The local deformability of the recess wall may be configuredsuch that the local changes in the shape of the recess wall, between theincreased pressure and decreased pressure condition, occur at a pressuredifference in a range up to 0.2 bar, or even at lower pressuredifferences.

According to a further embodiment of the first aspect of the inventionof Chapter 3, the pressure in a said at least one pressure chamber may,in the decreased pressure condition, be higher than ambient airpressure.

Ambient air pressure is the pressure prevailing in the room where theuser of the mouthpiece is when using the mouthpiece. In general ambientair pressure is assumed to be about 1 bar absolute pressure, but theactual value of the ambient air pressure will depend amongst others fromthe height with respect to sea level and weather conditions.

According to a further embodiment of the first aspect of the inventionof Chapter 3, the pressure in a said at least one pressure chamber may,in the increased pressure condition, be at most 2 bar relative toambient air pressure, such as at most 1 bar relative to ambient airpressure.

According to a further embodiment of the first aspect of the inventionof Chapter 3, the pressure in a said at least one pressure chamber may,in the increased pressure condition, be at most 0.3 bar relative toambient air pressure, such as at most 0.2 bar relative to ambient airpressure. With a pressure of at most 0.3 bar the brushing action issatisfactory, whilst the risk of harm or injury in case the recess mightrupture is minimal. With a pressure of at most 0.2 bar the brushingaction is still satisfactory.

According to a further embodiment of the first aspect of the inventionof Chapter 3, the pressure in a said at least one pressure chamber is,in the decreased pressure condition, lower than ambient air pressure.

According to a further embodiment of the first aspect of the inventionof Chapter 3, the pressure in a said at least one pressure chamber may,in the decreased pressure condition, be in the range of −0.5 to +0.2 barrelative to ambient air pressure, such as in the range of −0.5 to 0 barrelative to ambient air pressure. With a decreased pressure of at least−0.5 bar the chance that the recess wall might become damaged is low.The decreased pressure may be in the range of −0.4 to −0.25 relative toambient air pressure. A decreased pressure in the range of −0.4 to −0.25bar relative to ambient air pressure can be realized with relativelycheap means. A decreased pressure with a value below zero relative toambient air pressure, means that, when decreasing pressure to thedecreased pressure condition, a vacuum is created in the pressurechamber. Using a pressure below ambient air pressure for the decreasedpressure condition means that the chances to damage the gum of the userare reduced considerably.

According to a second aspect of the invention of Chapter 3, which may beseparate from or in combination with one/or more other aspects of theinvention of Chapter 3, the invention of Chapter 3 provides a mouthpiecefor simultaneously brushing at a plurality of dental positions, like asworded in independent claim 73. To define this second aspect, a systemof three mutually orthogonal axes is defined, comprising an x-axis, any-axis, and a z-axis, the z-axis being a curved axis following thecontour of a dental arch—for example the dental arch of an adult human—, the x-axis and y-axis being perpendicular to each other and definingan xy-plane which is flat and perpendicular to the curved z-axis. Themouthpiece of this second aspect comprises a body provided with at leastone recess. As is also the case with the other aspects of this inventionof Chapter 3, in use this mouthpiece will be inserted in the mouth ofthe user. So the dimensions of the mouthpiece may be configured to allowinsertion into the mouth of a user. The at least one recess has a curvedlength direction extending parallel to the z-axis, an U-shapedcross-section transverse to the length direction, and is configured forencompassing, viewed in the curved length direction, a plurality of atleast 5 dental positions. The body comprises, per said recess, a recesswall delimiting the respective recess and provided with a pluralitybristles. As also may be the case in the other aspects of this inventionof Chapter 3, the bristles may be flexible and/or deformable. Eachbristle has a fixed end which is, at the recess wall, attached to thebody. The fixed ends of the bristles may for example be attached to therecess wall, but may also be attached to another part of the body. Eachbristle extends from the fixed end, into the recess, towards the freeend of the bristle, which free end is arranged in the recess. The bodyis according to this second aspect configured to subject, when a saidplurality of dental positions is encompassed in the recess, a multipleof said fixed ends of the bristles—for example each free end of eachbristle—reciprocatingly to a first back and forth pivot movement arounda first pivot axis, a second back and forth pivot movement around asecond pivot axis and a back and forth translation movement along atranslation axis, the first pivot axis, the second pivot axis and thetranslation axis being mutually perpendicular, the first pivot axisbeing parallel to the z-axis, and the second pivot axis and translationaxis extending in the xy-plane. Configuring the body to subject fixedends of the bristles to these movements, may be accomplished with—seealso the next paragraph—a said body comprising a pressure chamber and arecess wall which is locally deformable and carries the fixed ends ofthe bristles, but may also be accomplished with a different mounting ofthe fixed ends of the bristles and/or a different drive to subject thefixed ends of the bristles to these movements.

According to a further embodiment of the first and/or second aspect ofthe invention of Chapter 3, the local deformability of the recess wallmay be such that, when reciprocatingly increasing and decreasing thepressure in a said at least one pressure chamber and encompassing saidplurality of dental positions in the recess, each location of the recesswall is subjected to a first back and forth pivot movement around afirst pivot axis, a second back and forth pivot movement around a secondpivot axis and a back and forth translation movement along a translationaxis, the first pivot axis, the second pivot axis and the translationaxis being mutually perpendicular.

According to a further embodiment of the first and/or second aspect ofthe invention of Chapter 3, each bristle is at a root of the respectivebristle be attached to the recess wall, and the local deformability ofthe recess wall may be such that, when reciprocatingly increasing anddecreasing the pressure in a said at least one pressure chamber andencompassing said plurality of dental positions in the recess, the rootof each bristle is subjected to a first back and forth pivot movementaround a first pivot axis, a second back and forth pivot movement arounda second pivot axis and a third back and forth translation movementalong a translation axis, the first pivot axis, the second pivot axisand the translation axis being mutually perpendicular.

According to a further embodiment of the first and/or second aspect ofthe invention of Chapter 3, each respective bristle may be attached tothe recess wall in an attachment point; at each attachment point, alocal set of three mutually orthogonal axes may be defined, which localset comprises an x-axis, an y-axis and a z-axis, the z-axis being acurved axis defined by the curved length direction of the recess, thex-axis and y-axis defining an xy-plane perpendicular to the z-axis; andthe local deformability of the recess wall may be such that, whenreciprocatingly increasing and decreasing the pressure in a said atleast one pressure chamber and encompassing a said plurality of dentalpositions in the recess, the attachment points are subjected to one ormore movements from the group of: a first back and forth pivotingmovement around a first pivot axis, a second back and forth pivotingmovement around a second pivot axis, and a back and forth translatingmovement along a translation axis; wherein the first pivot axis isparallel to the z-axis and the second pivot axis and translation axisare in the xy-plane and mutually perpendicular. In addition to thesefirst, second and third back and forth movement, it is noted that therecess wall may also allow a fourth, fifth and sixth back and forthmovement which may further contribute to the brushing action, wherein,viewed at the location of the root of the bristle, the fourth back andforth movement is a back and forth translation movement in the directionof the z-axis, the fifth back and forth movement is a back and forthtranslation movement in the direction of the y-axis, and the sixth backand forth movement is a back and forth rotation movement around thex-axis.

According to a further embodiment of the first and/or second aspect ofthe invention of Chapter 3, the body may be provided with two saidrecesses, the openings of the U-shaped cross-sections of the tworecesses facing in mutually opposite directions. This allows upperdental positions and lower dental positions to be brushed at the sametime.

According to a further embodiment of the first and/or second aspect ofthe invention of Chapter 3, wherein the recess wall is, transverse tothe length direction, U-shaped in conformity with the U-shapedcross-section of the recess; wherein the U-shape of each recess walldefines two recess wall legs extending from a recess wall bottom, eachleg having a free end; wherein the free ends of the legs are providedwith end bristles; and wherein the body is configured

-   -   to shift the upper ends of the legs from inside the recess to        outside the recess when increasing the pressure in said at least        one pressure chamber, and    -   to decrease the vertical distance and to shift the upper ends of        the legs from outside the recess to inside the recess when        decreasing the pressure in said at least one pressure chamber        such that the end bristles are subjected to a back and forth        swivelling movement around an axis parallel to the length        direction when reciprocatingly increasing and decreasing the        pressure in a said at least one pressure chamber. A ‘roller        bellow functionality’ is introduced. The reciprocating shifting        of the ends of the legs from inside the recess to outside the        recess causes the end bristles into a back and forth swivelling        movement around an axis parallel to the curved length direction.        As a result the transitions of the teeth to the gums are        subjected to a special brushing action of these end bristles. As        is generally known, these transitions need careful cleaning        care. According to a third aspect of the invention of Chapter 3,        this ‘roller bellows functionality’ may also be applied separate        from the first and/or second aspect of the invention of Chapter        3, as may be worded, like in independent claim 79 (which has        been delimitated against the not pre-published        PCT/NL2018/050276), as follows: “A mouthpiece for simultaneously        brushing at a plurality of dental positions; wherein the        mouthpiece comprises a body provided with at least one recess;        wherein the said at least one recess has a curved length        direction and a U-shaped cross-section transverse to the length        direction and is configured for encompassing, viewed in the        curved length direction, a plurality of at least 5 dental        positions; wherein the body comprises, per recess, a flexible        recess wall delimiting the respective recess; wherein the recess        wall is lined with a plurality of bristles, each having one end        attached to the recess wall and extending from the recess wall        into the recess; wherein the body is provided with at least one        pressure chamber configured for containing a fluid under        pressure; wherein the body is configured to deform the recess        wall by reciprocatingly increasing and decreasing a pressure in        the at least one pressure chamber between a decreased pressure        condition and an increased pressure condition; wherein the        recess wall is, transverse to the length direction, U-shaped in        conformity with the U-shaped cross-section of the recess;        wherein the U-shape of each recess wall defines two recess wall        legs extending from a recess wall bottom, each leg having a free        end; and wherein the body is configured:    -   to shift the upper ends of the legs from inside the recess to        outside the recess when increasing a pressure in said at least        one pressure chamber, and    -   to shift the upper ends of the legs from outside the recess to        inside the recess when decreasing the pressure in said at least        one pressure chamber such that the end bristles are subjected to        a back and forth swivelling movement around an axis parallel to        the length direction when reciprocatingly increasing and        decreasing the pressure in a said at least one pressure        chamber”.

According to a further embodiment of the first and/or second and/orthird aspect of the invention of Chapter 3,

the body may be configured to subject the legs of the recess walls to areciprocating movement in the vertical direction when reciprocatinglyincreasing and decreasing pressure in a said at least one at least onepressure chamber.

According to a further embodiment of the first and/or second and/orthird aspect of the invention of Chapter 3,

the body may be configured to elongate the legs when increasing thepressure in the at least one pressure chamber and to shorten the legswhen decreasing the pressure in the at least one pressure chamber.Elongating and shortening of the legs causes the bristles on the legs tomove with respect to the dental positions in a length direction of thelegs.

According to a further embodiment of the first and/or second and/orthird aspect of the invention of Chapter 3, the body defines a referenceplane parallel to the curved length direction, the free ends of the legspointing away from the reference plane and an outer side of the bottomfacing the reference plane; wherein a vertical distance is defined as adistance, measured in a direction transverse to the reference plane,from the reference plane to the free ends of the legs; and wherein thebody is further configured:

-   -   to increase the vertical distance when increasing a pressure in        said at least one pressure chamber, and    -   to decrease the vertical distance when decreasing the pressure        in said at least one pressure chamber.        Increasing and decreasing the vertical distance causes the        bristles on the legs to move with respect to the dental        positions in the direction of the vertical distance.

According to a further embodiment of the first and/or second and/orthird aspect of the invention of Chapter 3, the mouthpiece may furthercomprise a meshwork fixed to the recess wall, wherein the meshwork isformed by nodes and mesh members, each said mesh member extending fromone said node to another said node, each said node connecting at leastthree said mesh members to each other, and wherein each node carries oneor more of said bristles or a tuft of said bristles. This ‘meshfunctionality’ simplifies production of a mouthpiece according to theinvention of Chapter 3. The mesh with bristles on the nodes can beproduced as a separate component, separate from and preceding themanufacturing of the mouthpiece. During or after manufacturing of themouthpiece, the mesh with bristles can be arranged to lie over therecess wall. According to a fourth aspect of the invention of Chapter 3,this ‘mesh functionality’ may also be applied separate from the firstaspect and/or second and/or third aspect of the invention of Chapter 3,as may be worded, like in independent claim 83 (which has beendelimitated against the not pre-published PCT/NL2018/050276), asfollows: “A mouthpiece for simultaneously brushing at a plurality ofdental positions; wherein the mouthpiece comprises a body provided withat least one recess; wherein the at least one recess has a curved lengthdirection and a U-shaped cross-section transverse to the lengthdirection and is configured for encompassing, viewed in the curvedlength direction, a plurality of at least 5 dental positions; whereinthe body comprises, per said recess, a recess wall delimiting therespective recess; wherein the recess wall is lined with a plurality ofbristles extending from the recess wall into the recess; wherein thebody may optionally be provided with at least one pressure chamberconfigured for containing a fluid under pressure, the body optionallybeing configured to deform the recess wall by reciprocatingly increasingthe pressure in the at least one pressure chamber from a decreasedpressure condition to an increased pressure condition and decreasingpressure in the at least one pressure chamber from an increased pressurecondition to a decreased pressure condition; wherein the mouthpiecefurther comprises a meshwork lying against the recess wall or fixed tothe recess wall; and wherein the meshwork is formed by nodes and meshmembers, each said mesh member extending from one said node to anothersaid node, each said node connecting at least three said mesh members toeach other, and wherein each node carries one or more of said bristlesor a tuft of said bristles.”

According to a further embodiment of the first and/or second and/orthird and/or fourth aspect of the invention of Chapter 3, the meshworkmay lie in a cut away of the recess wall, or may embedded in material ofthe recess wall, or may be adhered or glued to the recess wall, or maybe positioned in the pressure chamber and overlapping holes in therecess wall through which the tuft of bristles extend externally fromthe recess wall.

According to a further embodiment of the first and/or second and/orthird and/or fourth aspect of the invention of Chapter 3, wherein eachrespective mesh member has a length direction defined by an imaginarystraight line extending between two said nodes, between which nodes therespective mesh member extends, the mesh members may be stretchable intheir length direction or at least a part of the mesh members isstretchable in their length direction. The mesh-members beingstretchable allows the mesh to follow deformations of the recess wall,like stretching or like local changes in shape of recess wall duringincreasing and decreasing pressure. The stretchable mesh members may beelastically stretchable and/or may have, viewed in the length directionof the respective mesh member, a zig-zag structure configured forproviding said stretchability.

According to a further embodiment of the first and/or second and/orthird and/or fourth aspect of the invention of Chapter 3, the meshmembers or at least part of the mesh members may be configured to breakwhen a predetermined force (like a stretching force) acting on therespective mesh members, is exceeded. The mesh-members being breakableallows the mesh to follow deformations of the recess wall, likestretching or like local changes in shape of recess wall duringincreasing and decreasing pressure. Additionally, the mesh-members beingbreakable allows the nodes of the mesh being attached to the recesswall, whilst the mesh is still one unit, during manufacturing of themouthpiece and subsequently breaking these mesh-members, for example byexcessively increasing pressure in the pressure chambers during or atthe end of the production of the mouthpiece in order to allow, at use,the nodes to move independently from each other together with movementof the recess wall due to increasing and decreasing pressure.

According to a further embodiment of the first and/or second and/orthird and/or fourth aspect of the invention of Chapter 3, the at leastone recess may be configured for encompassing, viewed in its curvedlength direction:

-   -   the dental positions in the range from a central incisor up to a        first molar; and/or    -   the dental positions in the range from a central incisor up to a        second molar; and/or    -   the dental positions in the range from a right second premolar        up to a left second premolar; and/or    -   the dental positions in the range from a right first molar up to        a left first molar; and/or    -   the dental positions in the range from a right second molar up        to a left second molar.        The curved length direction of the recess defining a curved        length axis, this means that the length of the length axis of        the recess (or recess wall) spans a distance:    -   at least equal to the distance from a central incisor up to a        first molar; and/or    -   at least equal to the distance from a central incisor up to a        second molar; and/or    -   at least equal to the distance from a right second premolar up        to a left second premolar; and/or    -   at least equal to the distance from a right first molar up to a        left first molar; and/or    -   at least equal to the distance from a right second molar up to a        left second molar.        Further in addition, the curved length axis may have a shape        similar to the shape of a human dental arch or similar to at        least part of the shape of a human dental arch.

According to a further embodiment of the first and/or second and/orthird and/or fourth aspect of the invention of Chapter 3, the bristlesmay, at their ends attached to the recess wall, be fixed relative to therecess wall.

According to a further embodiment of the first and/or second and/orthird and/or fourth aspect of the invention of Chapter 3, the recesswall may be lined with at least 5 bristles per cm². The recess wall mayfor example be lined with 40 to 200 bristles per cm² in case of forexample elastomeric bristles or with 1000 to 6000 bristles per cm² incase of for example bristles of nylon.

According to a further embodiment of the first and/or second and/orthird and/or fourth aspect of the invention of Chapter 3, wherein therecess wall is, transverse to the length direction, U-shaped inconformity with the U-shaped cross-section of the respective recess, andwherein a central axis is defined as the mirror axis of the U-shape andthe U-shape of the recess defines two legs extending in the direction ofthe central axis, the legs may be provided or lined with bristlesextending at an angle in the range of 0 to 90 degrees, such as in therange of 30 to 60 degrees, with respect to the central axis. When thebristles extend at such an angle, they point so to say, in a neutralposition, towards the gum. When increasing pressure the pressurechamber, the recess wall will be pressed towards the dental positionsresulting in the bristles tips being be pushed towards the gum, which inturn contributes to the brushing action. For example, the free ends ofthe legs may be provided with bristles extending at an angle in therange of 45 to 90 degrees, such as in the range of 40 to 70 degrees,with respect to the central axis.

According to a further embodiment of the first and/or second and/orthird and/or fourth aspect of the invention of Chapter 3, the recesswall may be elastically deformable.

BRIEF DESCRIPTION OF THE DRAWINGS OF CHAPTER 3

The invention of Chapter 3 will be explained further with reference tothe FIGS. 27-45. In these figures:

FIG. 27 shows a lower dental arch with dental positions and a system ofthree orthogonal axes defining a dental arch.

FIG. 28 shows a perspective view of a mouthpiece according to a firstembodiment of the first aspect of the invention of Chapter 3.

FIGS. 29a, 29b and 29c schematically show cross-sectional views of apart of second embodiment of a mouthpiece according to the first aspectof the invention of Chapter 3, in different respective operationalstates thereof, the cross sectional views corresponding with the crosssection as indicated with arrows XXVIII-XXVIII in FIG. 28.

FIG. 30 schematically shows a top view of a third embodiment of themouthpiece according to the first aspect of the invention of Chapter 3.

FIGS. 31a, 31b, 31c schematically show cross-sectional views of a partof the third embodiment of a mouthpiece according to the first aspect ofthe invention of Chapter 3, in different respective operational statesthereof, the cross sectional views corresponding with the cross sectionas indicated with arrows XXX-XXX in FIG. 30.

FIGS. 32a, 32b, 32c, 32d give an elucidation of the second aspect of theinvention of Chapter 3 and of the local deformability of the recess wallof a mouthpiece according to the first aspect of the invention ofChapter 3.

FIGS. 33a and 33b give an elucidation a recess wall which is not locallydeformable.

FIGS. 34a and 34b give a further elucidation of the local deformabilityof the recess wall of a mouthpiece according to the first aspect of theinvention of Chapter 3.

FIG. 35 gives another further elucidation of the local deformability ofthe recess wall of a mouthpiece according to the first aspect of theinvention of Chapter 3.

FIGS. 36a, 36b, 36c schematically show cross-sectional views of a partof a first embodiment of a mouthpiece according to the third aspect ofthe invention of Chapter 3, in different respective operational statesthereof.

FIGS. 37a, 37b, 37c schematically show cross-sectional views of a partof a second embodiment of a mouthpiece according to the third aspect ofthe invention of Chapter 3, in different respective operational statesthereof.

FIG. 38 shows schematically a mesh structure according to a firstembodiment of the third aspect of the invention of Chapter 3.

FIGS. 39a and 39b show schematically a mesh structure according to asecond embodiment of the fourth aspect of the invention of Chapter 3.

FIGS. 40a and 40b show schematically a mesh structure according to athird embodiment of the fourth aspect of the invention of Chapter 3.

FIGS. 41a and 41b show schematically a mesh structure according to afourth embodiment of the fourth aspect of the invention of Chapter 3.

FIGS. 42a and 42b show schematically a mesh structure according to afifth embodiment of the fourth aspect of the invention of Chapter 3.

FIGS. 43a and 43b show schematically a mesh structure according to asixth embodiment of the fourth aspect of the invention of Chapter 3.

FIG. 44 shows schematically a detail with a flexible recess wall.

FIG. 45 shows schematically a dental cleaning device according to theinvention of Chapter 3 comprising a mouthpiece according to theinvention of Chapter 3.

DETAILED DESCRIPTION OF THE FIGURES OF CHAPTER 3

FIG. 27 shows in perspective view, highly schematically a part of anupper dental arch 601 with dental positions 602-614. Each dentalposition is indicated with a vertical dashed line. Each dental positionusually comprises a tooth which is named according to a nomenclatureknown to each dentist. Using this nomenclature:

-   -   dental position 602 is the position of the left ‘second molar’,        present in FIG. 27;    -   dental position 603 is the position of the left ‘first molar’,        missing in FIG. 27;    -   dental position 604 is the position of the left ‘second        premolar’, present in FIG. 27;    -   dental position 605 is the position of the left ‘first        premolar’, present in FIG. 27;    -   dental position 606 is the position of the left ‘canine’,        present in FIG. 27;    -   dental position 607 is the position of the left ‘lateral        incisor’, missing in FIG. 27;    -   dental position 608 is the position of the left ‘central        incisor’, present in FIG. 27;    -   dental position 609 is the position of the right ‘central        incisor’, present in FIG. 27;    -   dental position 610 is the position of the right ‘lateral        incisor’, present in FIG. 27;    -   dental position 611 is the position of the right ‘canine’,        present in FIG. 27;    -   dental position 612 is the position of the right ‘first        premolar’, present in FIG. 27;    -   dental position 613 is the position of the right ‘second        premolar’, present in FIG. 27;    -   dental position 614 is the position of the right ‘first molar’,        present in FIG. 27;        In FIG. 27 the dental position of the right ‘second molar’ is        not shown, and also the dental positions of the right and left        ‘third molar’, also called wisdom tooth, are not shown. Similar        the lower jaw has a similar number of dental positions, which        are in accordance with said nomenclature similarly named.

Reference number 615 indicates the lingual side of the arch of dentalposition. The lingual side 615 is the inner side of the arch of dentalpositions, which inner side faces the tongue. Reference number 616indicates the facial side of the arch of dental positions. The facialside 616 is the outer side of the arch of dental positions, which outerside faces the face, like the cheeks and lips.

The mouthpiece according to the invention of Chapter 3 is configured forsimultaneously brushing at a plurality of dental positions. In case atooth is present, the tooth of the respective dental position will bebrushed. Due to the local deformability of the recess wall according tothe invention of Chapter 3, the remnants at a dental position, like thegum, will be brushed in case a tooth may be missing and the teethadjacent the location of the missing tooth will be additionally brushedby bristles intended for the location of the missing tooth.

FIG. 27 further shows a system of three mutually orthogonal axes,comprising an x-axis x, an y-axis y and a z-axis z. The z-axis z is acurved axis following the contour of the dental arch 601. The x-axis xand y-axis y are perpendicular to each other and define an xy-planewhich is essentially flat and perpendicular to the dental arch 601, i.e.each xy-plane intersecting a location on the z-axis is, at thatlocation, perpendicular to the curved z-axis z. The z-axis z defines acurved length direction. The z-axis Z and y-axis Y define a curvedzy-plane, with viewed along the z-axis, an arch shape similar to theshape of the arch of dental positions. Further, the z-axis Z and X-axisX define a zx-plane.

FIG. 28 shows schematically a perspective view of a mouthpiece 620according to the invention of Chapter 3. The mouthpiece 620 comprises abody 621 provided with a first recess 622. This first recess 622 has,viewed along the z-axis of FIG. 27, a curved length direction and,viewed in the xy-plane of FIG. 27, an U-shaped cross section. The firstrecess 622 is delimited by a recess wall 623, which is in the xy-planeU-shaped. The recess wall 623 is lined with a plurality of bristles 624,each having one end, called the root 649, attached to the recess wall623 and extending from the recess wall 623 into the first recess 622.

Reference 626 indicates a nipple configured for connecting themouthpiece to a pumping and/or suctioning device. The mouthpiece 620further has a right half 627 and a left half 628, which halves come soto say together at nipple 626.

Reference 625 indicates a curved dividing line, which defines a mirrorplane parallel to the xz-plane as defined in FIG. 27. The mouthpiece asshown in FIG. 28 is so to say mirror symmetrical with respect to thismirror plane, meaning that there is a second recess (not visible in FIG.28) opposite the first recess 622, which second recess is lined withbristles as well. This second recess is however visible in amongstothers FIG. 29, where it has been indicated with reference number 622 aswell. It is noted that the first recess may have a shape different thanthe shape of the second recess because the (teeth of the) upper andlower arch of dental positions have different shapes.

The recesses 622 are configured to encompass an entire dental arch fromthe dental position of the right third or second molar to the dentalposition of the left third respectively second molar. The recesses 622may also be configured to encompass a part of an arch of dentalpositions, this part comprising at least five dental positions, forexample from the dental position of a central incisor to the dentalposition of a second premolar or to the dental position of a first molaror a dental position of a second molar.

FIG. 29 shows cross-sections according to arrows XXVIII in FIG. 28 of aright part of a second embodiment of the mouthpiece 700 according to theinvention of Chapter 3 in different pressure conditions. In FIG. 29 samereference numbers have been used as in FIG. 28 for similar parts.

The mouthpiece of FIG. 28 and the mouthpiece of FIG. 29 may beessentially the same, FIG. 28 showing a perspective view and FIG. 29showing a cross section XXVIII-XXVIII of part of the mouthpiece of FIG.28. The main difference then is in the bristles. In FIG. 28 the bristles624 are relatively thick and may be made as one integral part with therecess wall 623, whilst in FIG. 29 the bristles are provided as tufts629 of relatively thin bristles 624. Each tuft 629 may have a base 636which carries the bristles 624 at their roots 649 and is attached to therecess wall.

As shown in FIG. 29, the mouthpiece 700 has a body 621 having in itsupper side a first recess 622 and in its lower side a second recess 622.Both recesses 622 are delimitated by a flexible recess wall 623. Incross-section parallel to the xy-plane as defined in FIG. 27, the recesswalls 623 are U-shaped and have a recess wall bottom 634 and two recesswall legs 633 extending from the recess bottom wall. The recess wall 623is covered with tufts 629 of bristles.

Inside the body there is provided a pressure chamber 635, which may, viathe nipple 626 (FIG. 28), be filled with a fluid. The fluid may be agas, like air, or a liquid, like water. In the embodiment as shown inFIG. 29, the mouthpiece has one pressure chamber. It is however notedthat the mouthpiece may comprise a plurality of pressure chambers, like5 pressure chambers as shown in FIGS. 30 and 31, or any other number ofpressure chambers. The not pre-published PCT/NL2018/050276 showsexamples of other numbers of pressure chambers in FIGS. 4, 5, 7, 9 and10, which are all within the scope of the present invention of Chapter3. In case of multiple pressure chambers, all the pressure chambers orgroups of pressure chambers may according to the invention of Chapter 3be in fluid communication with each other, similar as is described inthe not pre-published PCT/NL2018/050276.

As shown in FIG. 29, the mouthpiece may comprise an internal supportstructure of a material which is rigid relative to the material of therecess wall 623. This support structure may structure comprise a lingualplate 630 and a facial plate 632, both extending along, for exampleparallel to, the curved zy-plane defined in FIG. 27 and consequently,viewed along the z-axis, having a U-shape. In order to keep the lingualplate 630 and facial plate 632 at a distance from each other, thesupport structure may comprise one or more spacers 631. These one ormore spacers 631 may for example be a multiple of bars or wires or asingle plate which may extend essentially parallel to the zx-plane asdefined in FIG. 27. In case of a single plate as spacer, this plate maydivide the pressure chamber 635 in two pressure chambers, an upper oneand a lower one. These two pressure chambers may be in fluidcommunication with each other via one or more through holes through theplate. In case of large through holes and/or a large number of throughholes the two pressure chambers may effectively be one single pressurechamber.

FIGS. 29a, 29b and 29c schematically depict cross-sectional views of themouthpiece 700, in different respective operational states thereof. Thiscross-sectional view might be about the same all over the length axisZ—as defined in FIG. 27—of the dental arch.

The single pressure chamber 635 comprises a first flexible recess wall623 delimiting the first recess 622 (the upper one in FIG. 29) and asecond flexible recess wall 623 delimiting the second recess 622 (thelower one of FIG. 29). The first and second recess walls are deformable,in particular by increasing or decreasing the pressure in the pressurechamber 623. The flexible recess walls 623 may be made from an elasticmaterial, such as a rubberlike material. The flexible recess walls 623may also be made from a non-elastic material. The material of theflexible recess walls 623 may keep a predetermined shape when there issubstantially no, or a low, pressure difference across an inner side andan outer side of the flexible recess walls 623.

The mouthpiece 700 is configured for the tufts 629 of bristles 624 toengage the tooth surface of teeth of a dental arch or, in case one ormore dental positions the tooth might be missing, to engage the gum atthe respective dental position(s) at least when the pressure in thepressure chamber 635 is increased. In case a tooth might be missing at adental position, especially the tufts 629 of bristles at the free endsof the recess wall legs 633 will engage the gum at the empty dentalposition.

Viewed in length direction Z of the dental arch—as defined in FIG. 27 —,the tufts 629 of bristles 624 may be arranged at about the same densityas viewed in the cross-sections shown in FIGS. 29a, 29b , 29 c.

FIG. 29a illustrates a first operational state, also called intermediatestate, of the mouthpiece 700. The pressure in the pressure chamber 635may in the intermediate state be equal to ambient air pressure, lowerthan ambient air pressure or higher than ambient air pressure.

FIG. 29b illustrates a second operational state of the mouthpiece 700when the pressure chamber 635 is in increased pressure condition, forexample by feeding a fluid to the pressure chamber 635, or increasing anamount of fluid in the pressure chamber 635. As can be seen in FIG. 29b, as a result of increasing pressure, the recess walls 623 are so to saycompacted to narrow the recess 622 (with respect to FIG. 29a ), wherebythe bristles 624, in particular the free ends thereof, may engage toothsurfaces firmly and/or may be deformed against tooth surfaces.

FIG. 29c illustrates a third operational state of the mouthpiece 700when the pressure in the pressure chamber 635 is decreased, for exampleby discharging a fluid from the pressure chamber 635, or decreasing anamount of fluid in the pressure chamber 635. As can be seen in FIG. 29c, as a result of decreasing pressure, the flexible recess walls 623 are,compared with FIG. 29a , so to say dilated to enlarge the recess 622,whereby the bristles 624, in particular the free ends thereof, lessfirmly engage tooth surfaces (or do not engage tooth surface at all)and/or become less deformed against the tooth surfaces.

By a suitable cycle of increasing and decreasing pressure in thepressure chamber 635 to go from the first operational state to thesecond operational state, then from the second operational state to thefirst operational state, then from the first operational state to thethird operational state, followed by a return to the first operationalstate, and subsequently repeating such cycle, a most effective brushingaction of the mouthpiece can be obtained. The bristles 624 attached tothe recess wall bottom 634 generally perform an upward and downwardmotion during such cycling, and the bristles 624 at the recess wall legs633 generally perform a sideways motion to and fro during such cyclingin the direction of the x-axis as defined in FIG. 27. Due to the recess622 alternatively narrowing and widening when reciprocatingly increasingand decreasing pressure, the bristles 624 at the recess wall legs willalso be subjected to a back and forth pivoting around the z-axis asdefined in FIG. 27, resulting in a sweeping movement of the bristles inthe direction of the y-axis as defined in FIG. 27.

It is noted that, in the operational state of FIG. 29c (decreasedpressure condition), the pressure in the pressure chamber 635 may be avacuum, i.e. a pressure lower than ambient air pressure. When in theoperational state of FIG. 29c (increased pressure condition) thepressure in the vacuum chamber is a vacuum, for example 0.7 bar, thepressure in the pressure chamber 635 may, in the operational state ofFIG. 29b , be either a vacuum, ambient air pressure or a pressure higherthan ambient air pressure. Additionally, it is noted that it is alsopossible that in the operational states of FIGS. 29b as well as 29 c thepressure in the pressure chamber may be both higher than ambient airpressure or that in the operational state of FIG. 29b the pressure inthe pressure chamber is about ambient air pressure whilst in theoperational state of FIG. 29c the pressure in the pressure chamber ishigher than ambient air pressure.

Just by way of example to give some indication of dimensions andreferring to FIG. 27, for an adult human the width of a teeth element inthe X direction varies, depending on the dental position, between about2 to 12 mm. Taking into account that it is desired to keep themouthpiece as small as possible, the internal width of the U-shape ofthe recess wall in the X direction is to be kept as small as possibleand may be about 0 to 4 mm wider than the width of the respective tooth.By way of example to give some indication of dimensions, the internalwidth of the U-shape of the recess wall, viewed in the X-direction ofFIG. 27, may be in the range of 0 to 20 mm, such as in the range of 2-12mm. The bristles may be up to 6 mm long. In case for example thebristles are 3 to 4 mm long, this means that between the bristlesextending from opposing recess wall legs 633 no interspace or a limitedamount of interspace of about 2-4 mm is left. In FIG. 29, theseinterspaces are shown exaggerated. Further by way of example to givesome indication of dimensions, the U-shape of the recess wall may have,viewed in the Y-direction of FIG. 27, an internal height in the range of3 to 20 mm, such as in the range of 5 to 10 mm. These internal width andinternal height measures are indicative for an adult human. For a childor for animals these measures might be different.

FIG. 30 schematically depicts a top view of a third embodiment 710 of amouthpiece according to the invention of Chapter 3. FIGS. 31a, 31b and31c schematically depict cross-sectional views, according to the arrowsXXX-XXX in FIG. 30, of the mouthpiece 710, in different respectiveoperational states thereof. This cross-sectional view might be about thesame all over the length axis Z—as defined in FIG. 27—of the dentalarch.

Taking into account that the mouthpiece 710 of FIGS. 30-31, is verysimilar to the mouth piece 700 of FIG. 29, the same reference numbershave been used for same or similar parts of the mouthpiece 710 as havebeen used in relation to FIGS. 28-29.

There are essentially two differences between the mouthpiece 700 of FIG.29 and the mouthpiece 710 of FIGS. 30-31. Each one of these differencesmay be applied separately to the mouthpiece of FIG. 28 and/or FIG. 29without applying the other difference.

The first difference is that the mouthpiece of FIGS. 30-31 has fivepressure chambers 635 a, 635 b, 635 c, 635 d and 635 e. In FIG. 30 thepressure chambers 635 a, 635 c and 635 e have been made visible by meansof shaded grey areas. As can also be seen in FIG. 30, the nipple 626 hasa channel 637 a for providing a fluid communication with an externalpressure source. This channel 637 a debouches in pressure chambers 635 cand 635 a (not shown in FIG. 30). The channel 637 b connects thepressure chambers 635 c and 635 a with the pressure chamber 635 e andprovides a fluid communication between these chambers. The channel 637 cconnects the pressure chamber 635 e with the pressure chambers 635 a and635 b and provides a fluid communication between these chambers.Overall, all pressure chambers 635 a, 635 b, 635 c, 635 d and 635 e arein fluid communication with each other so that they may act as onesingle pressure chamber, like the pressure chamber 635 of mouthpiece700. Similar like described in relation to FIGS. 29a, 29b, and 29c alsothe mouthpiece 710 may have 3 operational states or two operationalstates in case one might be left out. For description of the operationalstates shown in FIGS. 31a, 31b and 31c reference is made to thedescription of FIGS. 29a, 29b and 29 c.

The second difference is that the mouthpiece of FIGS. 30-31 has aslightly different support structure. The lingual plate 630 and facialplate 632 of the mouthpiece 710 are arranged on the outside of the body621 instead of embedded inside the body as is the case in the mouthpiece700. Also the lingual plate 630 and a facial plate 632 of mouthpiece 710both extend along the curved zy-plane defined in FIG. 27 andconsequently, viewed along the z-axis, have a U-shape. In the embodimentof FIGS. 30 and 31, the lingual plate 630 and facial plate 632 may bekept at a distance from each other by additional spacers, not shown, butalso the recess wall bottoms 634 may serve as such a spacer.

Referring to FIGS. 32-35, the local deformability of the recess wallaccording to the first aspect of the invention of Chapter 3 will now beexplained and also the second aspect of the invention of Chapter 3 willbe explained.

Up to here, with reference to FIGS. 27-31, a global deformability of therecess wall 623 has been described, which global deformability occursupon the actuation of the at least one pressure chamber 635 withbristles 624 or tufts 629 with bristles 624 attached on the recess wall623. However, according to the first aspect of the invention of Chapter3, the recess wall 623 is further configured to have a localdeformability. This local deformability of the recess wall 623 will nowbe elucidated with reference to FIGS. 32a, 32b, 32c and 32 d.

FIGS. 32a and 32b are basically identical. The difference is that inFIG. 32b only one tuft 629 is shown for illustrative purpose, whilst inFIG. 32a a plurality of tufts 629 is shown.

FIGS. 32a and 32b show schematically a dental arch 601 and a flexiblerecess wall leg 633 of the flexible recess wall 623 on the facial sideof the dental arch 601. This flexible recess wall leg 633 is locallydeformable.

As these FIGS. 32a and 32b are for purpose of elucidation, the rest ofthe recess wall leg 633 extending along the facial side of the dentalarch 601, the recess wall leg 633 extending along the lingual side ofthe dental arch 601 and the recess wall bottom 634 extending along theocclusal surface and optionally the incisal edge are not shown. Thesenot shown parts of the recess wall 623 may all also be configured tohave a local deformability.

FIGS. 32a and 32b show the local deformability of the flexible recesswall 623, especially the local deformability of a recess wall leg 633,due to increasing and decreasing the pressure in the pressure chamber.As one can see, the recess wall leg 633 has, viewed along the z-axis anirregular shape, which follows the irregularities of the dentalpositions of the dental arch 601. For illustrative purpose, theirregular shape of the recess wall leg 633 almost precisely mates withthe irregular shape of the dental arch 601 adjacent the recess wall leg633. As will be clear, the irregular shape of the recess wall leg 633may be less pronounced than the irregular shape of the dental arch 601.

FIGS. 32a and 32b show the recess wall leg 633 in increased pressurecondition. The main direction of the pressure on recess wall leg 633, asshown in FIGS. 32a and 32b , is in the direction of the x-axis. Whendecreasing pressure, the recess wall leg 633 moves away from the dentalarch 601, decreasing the pressure exerted by the tufts 629 on the tooth640. When increasing pressure on the recess wall leg 633 again, therecess wall leg 633 moves towards the dental arch 601. This alternatingmovement in the direction of the x-axis is the first dimension of thebrushing movement realized with the mouth piece according to theinvention of Chapter 3.

When decreasing the pressure on the flexible recess wall leg 633, theflexible recess wall leg 633 will not only move away from the dentalarch 601, but, due to the local deformability, the flexible recess wallleg 633 will also tend to return to a less pronounced irregular shape inthe decreased pressure condition. This less pronounced irregular shapewhich may be a continuously curved shape parallel to the z-axis in casethe flexible wall part moves sufficiently far away from the dental archor may be or a shape still with relief, but with less relief then in theincreased pressure condition. This local change of the shape of therecess wall 623/recess wall leg 633 causes the tufts 629 attached at ornear that location to rotate around the y-axis resulting in a sweepingalong the facial surface of the teeth in the z-direction. Whenincreasing the pressure on the flexible recess wall leg 633, the tufts629 will tend to return to the position as shown in FIGS. 32a and 32b ,resulting in sweeping along the facial surface of the teeth in theopposite z-direction. This alternating sweeping movement in thedirection of the z-axis—which sweep is indicated by the double arrow 641in FIGS. 32a and 32b —is due to the local deformability of the flexiblewall part and is the second dimension of the brushing movement realizedwith the mouth piece according to the invention of Chapter 3.

The sweeping movement 641 in the direction of the z-axis, around they-axis, is caused by local irregularities of the dental arch 601 in thedirection of the z-axis and the local deformation of the flexible wallpart—at the location of the local irregularities, upon increasing anddecreasing pressure.

As shown schematically in FIG. 32c , irregularities of the dental arch601 in the direction of the y-axis y and the local deformability of theflexible recess wall leg 633 of the flexible recess wall 623 will,similarly, cause the tufts 629 to sweep in the y-direction around thez-axis, when increasing and decreasing the pressure in the pressurechamber 635. This alternating sweeping movement in the direction of they-axis and around the z-axis—which sweep is indicated by the doublearrow 642 in FIG. 32c —is due to the local deformability of the flexiblewall part and is the third dimension of the brushing movement realizedwith the mouth piece according to the invention of Chapter 3.

Referring to FIG. 32d , the local deformability of the recess wall alltogether results in, at least, an additional 2-dimensional brushingaction which is indicated in FIG. 32d by the cone 643. This additional2-dimensional brushing action is on top of the brushing action(s)already caused by the pulsating pressure. The main brushing actioncaused by the pulsating pressure is indicated in FIG. 32d by the doublearrow 644 and has been described above in relation to FIGS. 28-31. Thearrow 644 representing a third dimension, the overall brushing action atthe location L in FIG. 32d thus is a 3-dimensional brushing action: backand forth pivoting of bristles around the y-axis, back and forthpivoting of bristles around the z-axis and back and forth translating ofbristles along the x-axis. As will be clear, local deformability of therecess wall leg 633 at the lingual side and local deformability of therecess wall bottom 634 will result in similar manner in an additional2-dimensional brushing action.

More in general and viewed at the location of the root 649 of a randombristle, the additional 2-dimensional brushing action comprises a firstback and forth pivoting movement of the bristles and a second back andforth pivoting movement of the bristles, which two back and forthpivoting movements are on top of a third back and forth translationmovement caused by the pulsation of the pressure in the pressurechamber. Referring to the system of orthogonal axes as shown in FIG. 27and viewed at the location of a root of a bristle, the root of eachrandom bristle will lie in an xy-plane which is perpendicular to thecurved z-axis. Naming the xy-plane at the location of a root of abristle a local xy-plane, the back and forth translation movement at thelocation of the root of this bristle is in this local xy-plane and thusperpendicular to the z-axis. Taking into account that the recess wallhas, in this local xy-plane, essentially an U-shape in correspondencewith the U-shaped cross section of the recess, this back and forthtranslation movement is also about perpendicular to the U-shape of therecess wall in this local xy-plane. The first back and forth pivotingmovement is around the z-axis at the location L of the root of therespective bristle, i.e. around a first pivot axis perpendicular to thelocal xy-plane. The second back and forth pivoting movements is around asecond pivot axis which is perpendicular to the first pivot axis (orz-axis) as well as perpendicular to the third back and forth translationmovement. Further generalizing by leaving out the bristles, the localdeformability of the recess wall is such that, when reciprocatinglyincreasing and decreasing the pressure in a said at least one pressurechamber and encompassing said plurality of dental positions in therecess, each location of the recess wall is subjected to a first backand forth pivot movement around a first pivot axis, a second back andforth pivot movement around a second pivot axis and a back and forthtranslation movement along a translation axis, the first pivot axis, thesecond pivot axis and the translation axis being mutually perpendicular.

In addition to the above discussed first, second and third back andforth movement, it is noted that the recess wall also may allow afourth, fifth and sixth back and forth movement which may furthercontribute to the brushing action. The fourth back and forth movement isa back and forth translation movement in the direction of the z-axis atthe location of a root of a bristle, which may result from for exampleelasticity of the recess wall in the direction of the z-axis and adds afourth dimension to the brushing movement of the bristles. The fifthback and forth movement is a back and forth translation movement in thedirection of the y-axis at the location of a root of a bristle, whichmay result from, for example, elasticity of the recess wall in thedirection of the y-axis or translation of the recess wall in they-direction (see for example FIGS. 36b and 37b ) and adds a fifthdimension to the brushing movement of the bristles. The sixth back andforth movement is a back and forth rotation movement around the x-axisat the location of a root of a bristle, which may result from, forexample, local rotation of the recess wall around the x-axis and adds asixth dimension to the brushing movement of the bristles.

Referring to FIGS. 33 and 34, it will become clear that the localdeformability of the recess wall also results in improved interdentalbrushing and a more regular brushing pressure exerted on the dentalpositions. Both FIGS. 33 and 34 show for illustrative purpose, part of arecess wall leg 633 acting on a side of three teeth 640 in between whichinterdental spaces 638 are present. FIG. 33 shows the situation with arecess wall leg 633 which is configured with no local deformability,FIG. 33a showing a decreased pressure condition and FIG. 33b showing anincreased pressure condition, whilst FIG. 34 shows the situation which arecess wall leg 633 which is, according to the first aspect of theinvention of Chapter 3, configured to have a local deformability, FIG.34a showing a decreased pressure condition and FIG. 34b showing anincreased pressure condition.

When comparing the decreased pressure condition of FIG. 33a with theincreased pressure condition of FIG. 33b , it can be seen that theextent to which the interdental spaces 638 are reached by the bristles624 is determined by the length of the bristles and the distance d fromthe recess wall leg 633 to the sides of the teeth 633. The minimal valuefor the distance d might be smaller than shown in FIG. 33b . But due tothe recess wall leg 633 in FIG. 33 not being locally deformable, therecess wall leg 633 will maintain to be flat as shown in FIG. 33bresulting in that the distance e of the recess wall leg 633 to thedeepest point of the interdental recess is large compared with thesituation of FIGS. 34a and 34b . The minimal value for the distance d aswell as the distance e will be reached when the bent or straightbristles 24 in the areas 645 a, 645 b, 645 c, which are opposite theteeth 640 and not opposite the interdental spaces 638, prevent therecess wall leg 633 from moving further in the direction of the teeth640. Now, referring to FIG. 34, it will be seen that, due to the recesswall leg 633 locally deforming at locations 639 opposite the interdentalspaces 638, the bristles attached at or near the locations 639 of therecess wall leg will reach much deeper into the interdental spaces,resulting in a better cleaning of the interdental spaces 638.

Further referring to the increased pressure condition of FIG. 33b , itwill be clear that the pressure exerted by the bristles 624 in thex-axis direction varies considerable along the z-axis. At the areaaround an interdental position, this pressure is low and might be aboutzero. Referring to the increased pressure condition of FIG. 34b , itwill be clear that the pressure exerted by the bristles 624 in thex-axis direction is much more constant along the z-axis. The higherpressure exerted by the bristles in the areas of the interdental spaces638 according to FIGS. 34a and 34b , results in improved cleaning ofthese interdental spaces 638. Further, the pressure exerted by thebristles being much more constant along the z-axis means that there thepressure inside the pressure chamber is much more representative for thepressure exerted by the bristles along the dental arch. Exceeding themaximum allowable bristle pressure exerted by the bristles on especiallythe vulnerable gum, can thus be prevented much more reliable.

Referring to FIG. 35, an example of further location 646 with localdeformation of a recess wall leg 633 is shown in increased pressurecondition. Such a local deformation at location 646 may be caused by thebristles 624 pushed—so to say—flat towards the recess wall leg 633 dueto the local deformability of the recess wall leg 633. When decreasingpressure, this local deformation 646 may disappear or become lesspronounced, allowing the bristles to—so to say—rise again. This resultsin further additional brushing action.

Although, the second aspect of the invention of Chapter 3 may—aselucidated above—may be achieved with the locally deformable recess wallaccording to the first aspect of the invention of Chapter 3, it will beclear that the second aspect of the invention of Chapter 3 may also berealized in a different manner, for example by mounting the fixed endsof the bristles individually or grouped in tufts on an individual driveper bristle or tuft of bristles, wherein the individual drive providesthe back and forth translation movement and wherein the mounting allowsfor the first and second back and forth pivot movement.

FIGS. 36 and 37 show two embodiments of the third aspect of theinvention of Chapter 3, the ‘roller bellow functionality’. FIG. 36 showsa mouthpiece 720 and FIG. 37 shows a mouthpiece 730. FIGS. 36 and 37 aremutually identical, except FIGS. 36b and 37b , where the differencebetween the mouthpiece 720 and mouthpiece 730 can be seen. Further themouthpieces shown in FIGS. 36 and 37 on the one hand and FIG. 29 on theother hand are identical, except for the ‘roller bellow functionality’which is absent in the mouthpiece 710 of FIG. 29 and for the spacer 631in FIGS. 36 and 37 being a plate dividing the single pressure chamber635 of FIG. 29 into two pressure chambers 635 a and 635 b in FIGS. 36and 37. The pressure chambers 635 a and 635 b are in fluid communicationwith each other, for example by means of one or more passages throughthe plate 631, so that the fluid in both pressure chambers 635 a and 635b will have the same pressure. The spacer 631 being a plate in themouthpieces 720 and 730 has nothing to do with the ‘roller bellowfunctionality’. Like in FIG. 29a , FIGS. 36a and 37a show a firstoperational state. Like in FIG. 29b , FIGS. 36b and 37b show a secondoperational state, the increased pressure condition. And like in FIG.29c , FIGS. 36c and 37c show a third operational state, the decreasedpressure condition. Taking into account the similarities between FIG. 29on the one hand and FIGS. 37 and 38 on the other hand, FIGS. 37 and 38use the same reference numbers for similar parts and for more details ofFIGS. 37 and 38 reference is made to the description of FIG. 29. Notwith standing all these similarities between FIG. 29 on the one hand andFIGS. 36 and 37 on the other hand, it is noted that the ‘roller bellowfunctionality’ according to the third aspect can be applied without (orin combination with) the ‘local deformability functionality of therecess wall’ according to the first aspect of the invention of Chapter3.

According to the third aspect of the invention of Chapter 3, the body isconfigured to shift the upper ends 647 of the recess wall legs 633 frominside the recess 622 to outside the recess 622 when increasing thepressure in the pressure chambers 635 a and 635 b. When shiftingoutwards the bristles 648 at the upper ends 647 of the recess wall legs633, which bristles are called end bristles 648, are subjected to arotational movement which topples the end bristles towards a moreupright position. This is shown in the increased pressure condition ofFIGS. 36b and 37b . Further, according to the third aspect of theinvention of Chapter 3, the body is configured to shift the upper ends647 of the recess wall legs 633 from outside the recess 622 (back) intothe inside of the recess 622 when decreasing the pressure in thepressure chambers 635 a and 635 b. When shifting inwards the endbristles 648, the end bristles 648 are subjected to a rotationalmovement which topples the end bristles 648 back towards a less uprightposition. This is shown in the decreased pressure condition of FIGS. 36cand 37c as well as in the pressureless condition shown in FIGS. 36a and37a . By reciprocatingly increasing and decreasing the pressure in theat least one pressure chamber 635 a, 635 b, the end bristles 648 aresubjected to a back and forth swiveling movement around an axis parallelto the z-axis as defined in FIG. 27.

The difference between the mouthpiece 720 of FIG. 36 and the mouthpiece730 of FIG. 37, is that in the embodiment of FIG. 37, the body isfurther configured to elongate the recess wall legs 633 when increasingpressure in the at least one pressure chamber 635 a, 635 b and toshorten the recess wall legs 633 when decreasing pressure in the atleast one pressure chamber 635 a, 635 b. The effect of this is that,viewed in the y-axis direction as defined in FIG. 27, the depth of therecesses 622 increases when increasing pressure and decreases whendecreasing pressure. This results in additional brushing actionespecially at the gum around the roots of the teeth. Elongating andshortening of the legs of the recess wall may for example be realized byfastening the center of the recess wall bottom 634 with respect to thespacer 631, as has been made visible, for illustrative purpose, only inFIGS. 37b and 37 c.

FIG. 38 schematically depicts a top view of an embodiment of a bristlesupport 650, having a net-shaped configuration, also called a meshwork.The meshwork has nodes 651 each having bristles 624 implanted therein.The meshwork further has mesh members 652, 653. Each mesh member 652,653 extends from one node 651 to another node 651. Each said node 651connects in this embodiment six mesh members 652, 653, but it is notedthat each node may also connect another number of mesh members, likethree, four or five mesh members. The nodes and a mesh members definemesh openings 655. Except the nodes provided at the side edges of themesh work, each node will connect at least three mesh members. Thebristle support 650 can lie against, or be adhered to, or be fixed to aflexible recess wall 623.

In order to allow a meshwork to follow the deformation of the flexiblerecess wall 623, which may be a 2 dimensional deformation as indicatedin FIG. 44, all or part of the mesh members may be:

-   -   elastically or non-elastically stretchable in their length;        and/or    -   may be configured to break when a predetermined stretching force        acting on the respective mesh member is exceeded.        In the latter case, the nodes may be attached to the flexible        wall part whilst the mesh members are free from the flexible        wall part.

In the meshwork of FIG. 38 all mesh-members may be elastically ornon-elastically stretchable in their length in order to allow themeshwork to follow a deformation of the flexible recess wall to whichthe meshwork will be attached (not shown).

FIG. 39 shows schematically a meshwork 660 with nodes 651 provided withbristles (not shown) and mesh members 661, 662. The mesh members 662have a zig-zag configuration, allowing expansion and contraction of themeshwork 660 in one direction from the state as shown in FIG. 39a to thestate as shown in FIG. 39b and vice versa, whilst the dimensions in theother direction do not change when the mesh members 661 have anunchangeable length. In case the mesh members 661 are for exampleelastically stretchable, also expansion and contraction of the meshwork660 in a direction perpendicular to the arrows of FIG. 39b will bepossible. Another way of allowing expansion and contraction of meshwork660 in two perpendicular directions, is to provide the mesh members 661with a zig-zag-structure as well, which results in a mesh work 670 likeshown in FIG. 40a in contracted state and in FIG. 40b in expanded state.This meshwork 670 has nodes provided with bristles (not shown) andzig-zag mesh members 671 and 672.

FIG. 41 shows a meshwork 680 having an auxetic structure. This auxeticmeshwork has nodes 651 provided with bristles (not shown) and meshmembers 681, 682 and can follow deformations in two perpendiculardirections from the state shown in FIG. 41a to the state shown in FIG.41b , and vice versa.

FIG. 42 shows a meshwork 690 having nodes 651 with bristles (not shown)and breakable mesh members 691 and 692. The nodes of this meshwork willbe attached to the recess wall 623 with the mesh members 691 and 692 notyet broken, as shown in FIG. 42a . Then the recess wall 623 will bedeformed and the mesh members 691 and 692 will break, resulting in thestate as shown in FIG. 42b . As the nodes are attached to the recesswall 623, the nodes will follow all subsequent deformations of therecess wall once the mesh members 691 and 692 have been broken. FIG. 43shows a variant 695 of the meshwork 690 of FIG. 42. As indicated themesh members 691 and 692 can be broken by exerting a pulling force alongthe diagonal direction.

FIG. 45 schematically depicts, in a partially cut-away perspective view,a dental cleaning device 800 comprising a handle member 802 and amouthpiece 804 coupled thereto. The mouthpiece 804 may be any mouthpiecedescribed in this application. The handle member 802 is provided with ahandle interface, and the mouthpiece 804 is provided with a mouthpieceinterface configured to be detachably coupled to the handle interface.The handle member 800 comprises a battery 810 for storing electricalenergy which can be fed to the battery 810 through a battery charginginterface 812. The battery 810 provides energy to a printed circuitboard, PCB, 814, to a main pumping unit comprising a motor 816, atransmission 818, a crank piston 820 and a piston pump 822, and tooptionally a mouthwash pump 824. A mouthwash capsule 830 containing amouthwash liquid may be removably accommodated in the handle member 800.The piston pump 822 may be a pneumatic pump. The mouthwash pump 824 maybe a hydraulic pump.

A brushing valve unit 840 is included in one or more ducts 842 leadingfrom the piston pump 822 to the mouthpiece 804, and in possible otherducts. A cleaning valve unit 850 is included in a duct 852 leading fromthe mouthwash pump 824 to the mouthpiece 804. The brushing valve unit840 and the cleaning valve unit 850 comprise electronic valves whichalso receive energy from the battery 810. The mouthwash pump 824 is influid communication with the mouthwash capsule 830 through a duct 854.

The operation of the dental cleaning device 800 is controlled by the PCB814. The PCB 814 may control the operation of the motor 816, theoperation of the mouthwash pump 824, and the operation of valvescomprised in the brushing valve unit 840 and in the cleaning valve unit850. In particular, when the dental cleaning device is used for brushingat dental positions, wherein a plurality of at least five dentalpositions teeth of a dental arch is encompassed by the mouthpiece 804,the PCB 814 may control the dental cleaning device 800 toreciprocatingly increasing and decreasing the pressure in at least onepressure chamber provided in the body of the mouthpiece 804.

The next following clauses 65-102 give examples of the above describedinventions of Chapter 3 and further aspects and embodiments of theseinventions of Chapter 3:

-   -   65] A mouthpiece for simultaneously brushing at a plurality of        dental positions;    -   wherein the mouthpiece comprises a body provided with at least        one recess;    -   wherein the at least one recess has a curved length direction        and a U-shaped cross-section transverse to the length direction        and is configured for encompassing, viewed in the curved length        direction, a plurality of at least 5 dental positions;    -   wherein the body comprises, per said recess, a flexible recess        wall delimiting the respective recess,    -   wherein the recess wall is optionally lined with a plurality of        bristles, each having one end attached to the recess wall and        extending from the recess wall into the recess; wherein the body        is provided with at least one pressure chamber configured for        containing a fluid under pressure;    -   wherein the body is configured to deform the recess wall by        reciprocatingly increasing and decreasing a pressure in the at        least one pressure chamber between a decreased pressure        condition and an increased pressure condition; and    -   characterized, in that the recess wall is configured to have        such a local deformability that, when reciprocatingly increasing        and decreasing the pressure in a said at least one pressure        chamber, the shape of the recess wall locally changes, wherein,        in the increased pressure condition, the shape of the recess        wall is locally adjusted to the local shape of the dental        positions encompassed by the recess wall whilst, in the        decreased pressure condition, the shape of the recess wall is        locally less adjusted to the local shape of the dental positions        encompassed by the recess wall than in the increased pressure        condition.    -   66] The mouthpiece according to clause 65,    -   wherein, viewed in the length direction along a lingual and        facial side of the dental positions encompassed by the recess        wall, the recess wall has in the decreased pressure condition        less relief than in the increased pressure condition.    -   67] The mouthpiece according to one of the clauses 65-66,    -   wherein the local deformability of the recess wall is configured        such that the local changes in the shape of the recess wall,        between the increased pressure condition and decreased pressure        condition, occur at a pressure difference in a range up to 2        bar, such as in a range up to 0.4 bar, the pressure difference        being defined as the pressure in the pressure chamber in the        increased pressure condition minus the pressure in the pressure        chamber in the decreased pressure condition.    -   68] The mouthpiece according to one of the clauses 65-67,    -   wherein, in the decreased pressure condition, the pressure in a        said at least one pressure chamber is higher than ambient air        pressure.    -   69] The mouthpiece according to one of the clauses 65-68,    -   wherein, in the increased pressure condition, the pressure in a        said at least one pressure chamber is at most 2 bar relative to        ambient air pressure, such as at most 1 bar relative to ambient        air pressure.    -   70] The mouthpiece according to one of the clauses 65-69,    -   wherein, in the increased pressure condition, the pressure in a        said at least one pressure chamber is at most 0.3 bar relative        to ambient air pressure, such as at most 0.2 bar relative to        ambient air pressure.    -   71] The mouthpiece according to one of the clauses 65-70,    -   wherein, in the decreased pressure condition, the pressure in a        said at least one pressure chamber is lower than ambient air        pressure.    -   72] The mouthpiece according to one of the clauses 65-71,    -   wherein, in the decreased pressure condition, the pressure in a        said at least one pressure chamber is in the range of −0.5 to        +0.2 bar relative to ambient air pressure, such as in the range        of −0.5 to 0 bar relative to ambient air pressure.    -   73] A mouthpiece for simultaneously brushing at a plurality of        dental positions;    -   wherein a system of three mutually orthogonal axes is defined,        comprising an x-axis, an y-axis, and a z-axis, the z-axis being        a curved axis following the contour of a dental arch, the x-axis        and y-axis being perpendicular to each other and defining an        xy-plane which is flat and perpendicular to the curved z-axis;    -   wherein the mouthpiece comprises a body provided with at least        one recess;    -   wherein the at least one recess has a curved length direction        extending parallel to the z-axis, a U-shaped cross-section        transverse to the length direction, and is configured for        encompassing, viewed in the curved length direction, a plurality        of at least 5 dental positions;    -   wherein the body comprises, per said recess, a recess wall        delimiting the respective recess and provided with a plurality        bristles;    -   wherein each bristle has a fixed end which is, at the recess        wall, attached to the body;    -   wherein each bristle extends from the fixed end, into the        recess, towards its free end, which is arranged in the recess;    -   wherein the body is configured to subject, when a said plurality        of dental positions is encompassed in the recess, a plurality of        said fixed ends of said bristles reciprocatingly to a first back        and forth pivot movement around a first pivot axis, a second        back and forth pivot movement around a second pivot axis and a        back and forth translation movement along a translation axis,        the first pivot axis, the second pivot axis and the translation        axis being mutually perpendicular, the first pivot axis being        parallel to the z-axis, and the second pivot axis and        translation axis extending in the xy-plane.    -   74] The mouthpiece according to one of the clauses 65-73,        wherein the local deformability of the recess wall is such that,        when reciprocatingly increasing and decreasing the pressure in a        said at least one pressure chamber and encompassing said        plurality of dental positions in the recess, each location of        the recess wall is subjected to a first back and forth pivot        movement around a first pivot axis, a second back and forth        pivot movement around a second pivot axis and a back and forth        translation movement along a translation axis, the first pivot        axis, the second pivot axis and the translation axis being        mutually perpendicular.    -   75] The mouthpiece according to one of the clauses 65-74,        wherein each bristle is at a root of the respective bristle        attached to the recess wall, and wherein the local deformability        of the recess wall is such that, when reciprocatingly increasing        and decreasing the pressure in a said at least one pressure        chamber and encompassing said plurality of dental positions in        the recess, the root of each bristle is subjected to a first        back and forth pivot movement around a first pivot axis, a        second back and forth pivot movement around a second pivot axis        and a back and forth translation movement along a translation        axis, the first pivot axis, the second pivot axis and the        translation axis being mutually perpendicular.    -   76] The mouthpiece according to one of the clauses 65-75,    -   wherein each respective bristle is attached to the recess wall        in an attachment point;    -   wherein, at each attachment point, a local set of three mutually        orthogonal axes is defined, which local set comprises an x-axis,        an y-axis and a z-axis, the z-axis being a curved axis defined        by the curved length direction of the recess, the x-axis and        y-axis defining an xy-plane perpendicular to the z-axis; and    -   wherein the local deformability of the recess wall is such that,        when reciprocatingly increasing and decreasing the pressure in a        said at least one pressure chamber and encompassing a said        plurality of dental positions in the recess, the attachment        points are subjected to one or more movements from the group of:        a first back and forth pivoting movement around a first pivot        axis, a second back and forth pivoting movement around a second        pivot axis, and a back and forth translating movement along a        translation axis; and    -   wherein the first pivot axis is parallel to the z-axis and the        second pivot axis and translation axis are in the xy-plane and        mutually perpendicular.    -   77] The mouthpiece according to one of the clauses 65-76,    -   wherein the body is provided with two said recesses, the        openings of the U-shaped cross-sections of the two recesses        facing in mutually opposite directions.    -   78] The mouthpiece according to one of the clauses 65-77,    -   wherein the recess wall is, transverse to the length direction,        U-shaped in conformity with the U-shaped cross-section of the        recess;    -   wherein the U-shape of each recess wall defines two recess wall        legs extending from a recess wall bottom, each leg having a free        end;    -   wherein the free ends of the legs are provided with end        bristles; and wherein the body is configured        -   to shift the free ends of the legs from inside the recess to            outside the recess when increasing the pressure in said at            least one pressure chamber, and        -   to shift the upper ends of the legs from outside the recess            to inside the recess when decreasing the pressure in said at            least one pressure chamber such that the end bristles are            subjected to a back and forth swivelling movement around an            axis parallel to the length direction when reciprocatingly            increasing and decreasing the pressure in a said at least            one pressure chamber.    -   79] A mouthpiece for simultaneously brushing at a plurality of        dental positions;    -   wherein the mouthpiece comprises a body provided with at least        one recess;    -   wherein said the at least one recess has a curved length        direction and a U-shaped cross-section transverse to the length        direction and is configured for encompassing, viewed in the        curved length direction, a plurality of at least 5 dental        positions; wherein the body comprises, per recess, a flexible        recess wall delimiting the respective recess,    -   wherein the recess wall is lined with a plurality of bristles,        each having one end attached to the recess wall and extending        from the recess wall into the recess; wherein the body is        provided with at least one pressure chamber configured for        containing a fluid under pressure;    -   wherein the body is configured to deform the recess wall by        reciprocatingly increasing and decreasing a pressure in the at        least one pressure chamber between a decreased pressure        condition and an increased pressure condition;    -   wherein the recess wall is, transverse to the length direction,        U-shaped in conformity with the U-shaped cross-section of the        recess; and    -   wherein the U-shape of each recess wall defines two recess wall        legs extending from a recess wall bottom, each leg having a free        end;    -   characterized, in that the free ends of the legs are provided        with end bristles; and in that the body is configured:        -   to shift the upper ends of the legs from inside the recess            to outside the recess when increasing a pressure in said at            least one pressure chamber, and        -   to shift the upper ends of the legs from outside the recess            to inside the recess when decreasing the pressure in said at            least one pressure chamber            such that the end bristles are subjected to a back and forth            swivelling movement around an axis parallel to the length            direction when reciprocatingly increasing and decreasing the            pressure in a said at least one pressure chamber.    -   80] The mouthpiece according to clause 78 or 79 or one of the        clauses 65-77,    -   wherein the body is configured to elongate the legs when        increasing the pressure in said at least one pressure chamber        and to shorten the legs when decreasing the pressure in said at        least one pressure chamber.    -   81] The mouthpiece according to one of the clauses 78-80,    -   wherein the body defines a reference plane parallel to the        curved length direction, the free ends of the legs pointing away        from the reference plane and an outer side of the bottom facing        the reference plane;    -   wherein a vertical distance is defined as a distance, measured        in a direction transverse to the reference plane, from the        reference plane to the free ends of the legs; and    -   wherein the body is further configured:        -   to increase the vertical distance when increasing a pressure            in said at least one pressure chamber, and        -   to decrease the vertical distance when decreasing the            pressure in said at least one pressure chamber.    -   82] The mouthpiece according to one of the clauses 65-81,    -   wherein the mouthpiece further comprises a meshwork fixed to the        recess wall; and    -   wherein the meshwork is formed by nodes and mesh members, each        said mesh member extending from one said node to another said        node, each said node connecting at least three said mesh members        to each other, and wherein each node carries one or more of said        bristles or a tuft of said bristles.    -   83] A mouthpiece for simultaneously brushing at a plurality of        dental positions;    -   wherein the mouthpiece comprises a body provided with at least        one recess;    -   wherein the at least one recess has a curved length direction        and a U-shaped cross-section transverse to the length direction        and is configured for encompassing, viewed in the curved length        direction, a plurality of at least 5 dental positions; and    -   wherein the body comprises, per said recess, a recess wall        delimiting the respective recess,    -   wherein the recess wall is lined with a plurality of bristles        extending from the recess wall into the recess;    -   characterized, in that the mouthpiece further comprises a        meshwork lying against the recess wall or fixed to the recess        wall, and in that the meshwork is formed by nodes and mesh        members, each said mesh member extending from one said node to        another said node, each said node connecting at least three said        mesh members to each other, and wherein each node carries one or        more of said bristles or a tuft of said bristles.    -   84] The mouthpiece according to clause 82 or 83, wherein the        meshwork lies in a cut away of the recess wall, or is embedded        in material of the recess wall, or is adhered or glued to the        recess wall, or is positioned in the pressure chamber and        overlapping holes in the recess wall through which the tuft of        bristles extend externally from the recess wall.    -   85] The mouthpiece according to one of clauses 82-84,    -   wherein each respective mesh member has a length direction        defined by an imaginary straight line extending between two said        nodes, between which nodes the respective mesh member extends;        and wherein the mesh members are stretchable in their length        direction or at least a part of the mesh members is stretchable        in their length direction.    -   86] The mouthpiece according to clause 85,    -   wherein the stretchable mesh members are elastically        stretchable.    -   87] The mouthpiece according to clause 85 or 86,    -   wherein the stretchable mesh members have, viewed in the length        direction of the respective mesh member, a zig-zag structure        configured for providing said stretchability.    -   88] The mouthpiece according to one of the clauses 82-87,    -   wherein the mesh members or at least part of the mesh members is        configured to break when a predetermined force, acting on the        respective mesh members, is exceeded.    -   89] The mouthpiece according to one of the clauses 65-88,    -   wherein the at least one recess is configured for encompassing,        viewed in its curved length direction, the dental positions in        the range from a central incisor up to a first molar.    -   90] The mouthpiece according to one of the clauses 65-89,    -   wherein the at least one recess is configured for encompassing,        viewed in its curved length direction, the dental positions in        the range from a central incisor up to a second molar.    -   91] The mouthpiece according to one of the clauses 65-90,    -   wherein the at least one recess is configured for encompassing,        viewed in its curved length direction, the dental positions in        the range from a right second premolar up to a left second        premolar.    -   92] The mouthpiece according to one of the clauses 65-91,    -   wherein the at least one recess is configured for encompassing,        viewed in its curved length direction, the dental positions in        the range from a right first molar up to a left first molar.    -   93] The mouthpiece according to one of the clauses 65-92,    -   wherein the at least one recess is configured for encompassing,        viewed in its curved length direction, the dental positions in        the range from a right second molar up to a left second molar.    -   94] The mouthpiece according to one of the clauses 65-93,    -   wherein the bristles are, at their ends attached to the recess        wall, fixed relative to the recess wall.    -   95] The mouthpiece according to one of the clauses 65-94,    -   wherein the recess wall is lined with at least 5 bristles per        cm², such as at least 10 bristles per cm².    -   96] The mouthpiece according to one of the clauses 65-95,    -   wherein the recess wall is, transverse to the length direction,        U-shaped in conformity with the U-shaped cross-section of the        respective recess;    -   wherein a central axis is defined as the mirror axis of the        U-shape and the U-shape of the recess defines two legs extending        in the direction of the central axis; and    -   wherein the legs are provided with bristles extending at an        angle in the range of 0° to 90°, with respect to the central        axis.    -   97] The mouthpiece according to clause 96,    -   wherein the free ends of the legs are provided with bristles        extending at an angle in the range of 30° to 90° with respect to        the central axis.    -   98] The mouthpiece according to one of the clauses 65-97,        wherein the recess wall is elastically deformable.    -   99] The mouthpiece according to one of the clauses 65-98,        wherein the recess wall is configured to be deformable with a        frequency of at least 1 Hz, such as in the range of 1-20 Hz or        in the range of 20-50 Hz or more.    -   100] Dental cleaning device comprising a mouthpiece according to        one of the clauses 65-99, and a pressure and/or suction device        configured to be in fluid communication with the at least one        pressure chamber and for reciprocatingly increasing and        decreasing the pressure in the pressure chamber.    -   101] Dental cleaning device according to clause 100, wherein the        pressure and/or suction device is furthermore configured to:        -   reciprocatingly increasing and decreasing the pressure in a            said at least one pressure chamber with a pressure            difference in a range up to 2 bar, such as in a range up to            0.4 bar, the pressure difference being defined as the            pressure in the pressure chamber in the increased pressure            condition minus the pressure in the pressure chamber in the            decreased pressure condition;    -   and/or        -   decrease the pressure in a said at least one pressure            chamber to decreased pressure condition with a pressure            higher than ambient air pressure;    -   and/or        -   increase the pressure in a said at least one pressure            chamber to an increased pressure condition of at most 2 bar            relative to ambient air pressure, such as at most 1 bar            relative to ambient air pressure;    -   and/or        -   to increase the pressure in a said at least one pressure            chamber to a increased pressure condition of at most 0.3 bar            relative to ambient air pressure, such as at most 0.2 bar            relative to ambient air pressure;    -   and/or        -   to decrease the pressure in a said at least one pressure            chamber to a decreased pressure condition with a pressure            lower than ambient air pressure;    -   and/or        -   to decrease the pressure in a said at least one pressure            chamber to a decreased pressure condition in the range of            −0.5 to +0.2 bar relative to ambient air pressure, such as            in the range of −0.5 to 0 bar relative to ambient air            pressure.    -   102] Method of operating a mouthpiece according to one of the        clauses 65-99, wherein:        -   the pressure in a said at least one pressure chamber is            reciprocatingly increased and decreased with a pressure            difference in a range up to 2 bar, such as up to 0.4 bar,            the pressure difference being defined as the pressure in the            pressure chamber in the increased pressure condition minus            the pressure in the pressure chamber in the decreased            pressure condition;    -   and/or        -   the pressure in a said at least one pressure chamber is            reciprocatingly decreased to decreased pressure condition            with a pressure higher than ambient air pressure and            increased to a pressure higher than the pressure in the            decreased pressure condition;    -   and/or        -   the pressure in a said at least one pressure chamber is            reciprocatingly increased to an increased pressure condition            of at most 2 bar, such as at most 1 bar, relative to ambient            air pressure and decreased to a pressure lower than the            pressure in the increased pressure condition;    -   and/or        -   the pressure in a said at least one pressure chamber            reciprocatingly increased to an increased pressure condition            of at most 0.3 bar relative to ambient air pressure, such as            at most 0.2 bar relative to ambient air pressure, and            decreased to a pressure lower than the pressure in the            increased pressure condition;    -   and/or        -   the pressure in a said at least one pressure chamber is            reciprocatingly decreased to a decreased pressure condition            with a pressure lower than ambient air pressure and            increased to a pressure higher than the pressure in the            decreased pressure condition;    -   and/or        -   the pressure in a said at least one pressure chamber is            reciprocatingly decreased to a decreased pressure condition            in the range of −0.5 to +0.2 bar relative to ambient air            pressure, such as in the range of −0.5 to 0 bar relative to            ambient air pressure, and increased to a pressure higher            than the pressure in the decreased pressure condition.

As follows from the above, the term ‘pressure chamber’ as usedthroughout this Chapter 3 is a chamber in which the pressure is changedbetween a decreased pressure condition and an increased pressurecondition. The decreased pressure condition and increased pressurecondition may both be a pressure below ambient air pressure, i.e. avacuum defined as a pressure between 0 and 1 bar. Alternatively, thedecreased pressure condition and increased pressure condition may bothbe a pressure above ambient air pressure, or one of these pressureconditions may be about ambient air pressure whilst the other is belowor above ambient air pressure.

Where in this Chapter 3 the terminology ‘pressure in the pressurechamber’ or similar terminology is used, it is the ‘pressure of thefluid in the pressure chamber’. It is the pressure of the fluid whichacts on the recess wall to cause local deformation. The pressure of thefluid may for example be increased by supplying additional fluid intothe pressure chamber or decreased by allowing fluid to leave thepressure chamber.

Taking into account the shape of the various dental positions/naturalteeth, the shape of the U-shaped cross section may vary along the lengthdirection of the recess/recess wall. In the region of the upper and orlower incisors, the U-shaped cross section may for example be V-shaped.

Where in this Chapter 3 the phrase ‘in a said at least one pressurechamber’ is used, this means ‘in the pressure chambers or in one or moreof said at least one pressure chamber’.

1-102. (canceled)
 103. A method of manufacturing a continuous recesswall lined with bristles for a mouthpiece for simultaneously brushing ata plurality of dental positions, the continuous recess wall having anarch-shaped length axis and, viewed transverse to the length axis, aU-shaped cross-section configured for encompassing said plurality ofdental positions, and the arch-shaped length axis having a length whichspans a distance at least equal to the distance from the left secondpre-molar to the right second premolar; wherein the method comprises aproviding step, in which an elongate, continuous, bristled sheet parthaving a first side lined with a plurality of bristles is provided, theelongate, bristled sheet part defining a length axis extending parallelto the bristled sheet part and, viewed transverse to the length axis, across-sectional shape, and wherein the elongate, continuous, bristledsheet part obtained in the providing step has an initial condition inwhich: the cross-sectional shape has an initial shape; and the lengthaxis is arch-shaped; wherein the method further comprises a transformingstep, in which the elongate, continuous, bristled sheet part obtained inthe providing step is transformed to a said continuous recess wallhaving a final condition; wherein in the final condition: thecross-sectional shape has a final U-shape; the length axis is archshaped; the first side is a concave inner side of the final U-shape; andwherein the first side is in the final condition more concave than inthe initial condition.
 104. The method according to claim 103, whereinthe final U-shape is defined by two legs and a bottom connecting theselegs, wherein a vertical axis is defined as extending transverse to thebottom between the legs; wherein, in the final condition, the bristleson the one leg and the bristles on the other leg extend from therespective leg towards each other; and wherein, in the final condition,the bristles on the legs are provided at an angle with respect to thevertical axis, the angle being in the range of 30° to 90°, with respectto the vertical axis.
 105. The method according to claim 103, whereintwo legs and a bottom connecting these legs are defined by the finalU-shape, a vertical axis is defined as extending transverse to thebottom, and the legs define, at each root of a said bristle on that leg,a tangent to the first side of the bristled sheet part, which tangentextends in a plane transverse to the length axis; wherein, in theinitial condition, the bristles extend parallel to the vertical axis;wherein, in the transforming step, the legs are bended towards eachother rotating each respective tangent through an angle of x° withrespect to the vertical axis such that the bristle associated to therespective tangent extends at an angle of x° with respect to thevertical axis in a direction pointing away from the bottom; wherein saidx° is in the range of the range of 30°-60°; and wherein the final angleof the legs with respect to the vertical axis is in the range of 0°-45°.106. The method according to claim 103, wherein the bristles have a rootend, a free end and a bristle body extending from the root end to thefree end; wherein the bristled sheet part obtained in the providing stepis produced by tufting, the tufting comprising: inserting a plurality ofnylon bristles or tufts of nylon bristles through a first sheet part toextend with the bristle body and free end from a front side of the firstsheet part, and to project with a root end at a back side of the firstsheet part; optionally providing a second sheet part against thebackside of the first sheet part; and fusing the root ends of thebristles with the first sheet part and/or the optional second sheetpart.
 107. The method according to claim 103, wherein the bristled sheetpart is, in the transforming step, transformed from the initialcondition to the final condition by thermoforming; wherein, viewed in adirection along the contour of the U-shape, the bristled sheet part isstretched by the thermoforming; wherein, in the final condition andviewed in the direction along the contour of the U-shape, the bristlesare distributed according to a predetermined final pattern; and wherein,in the initial condition, the distribution of the bristles on thebristled sheet part is configured such that, in the final condition andviewed in the direction along the contour of the U-shape, the bristlesare distributed according to the predetermined final pattern.
 108. Themethod according to claim 103, wherein the length axis has an initialcurvature in the initial condition and a final curvature in the finalcondition, the initial curvature being wider than the final curvature.109. The method according to claim 103, wherein the length axis has acurvature which is in the initial condition the same as in the finalcondition.
 110. The method according to claim 103, wherein the bristledsheet part has two boundary edges extending along the length axis at,viewed in a direction transverse to the length axis, a mutual distancefrom each other; and wherein, in the transforming step, the bristledsheet part is transformed by reducing the mutual distance between thetwo boundary edges.
 111. The method according to claim 103, wherein thebristled sheet part, obtained in the providing step: is delimited by aninner boundary edge and an outer boundary edge, extending along thelength axis at a distance from the length axis; is an integral part witha lingual frame member and facial frame member both being bow-shapedalong a respective bow curvature; and comprises, at the inner boundaryedge, an inner attachment member extending along the inner boundary edgeand attached to the lingual frame member, and, at the outer boundaryedge, an outer attachment member extending along the outer boundary edgeand attached to the facial frame member.
 112. The method according toclaim 111, wherein the providing step comprises the sub-steps: providingthe facial frame member and the lingual frame member; providing,separate from the facial and lingual frame member, the bristled sheetpart integral with the inner and outer attachment member; and attachingthe inner attachment member and outer attachment member to the lingualframe member respectively facial frame member; and wherein the inner andouter attachment member are configured as a side flap extending alongthe inner boundary edge respectively the outer boundary edge and to beattached to the lingual respectively facial frame member.
 113. Themethod according to claim 111, wherein, in the providing step, thebristled sheet part, the facial frame member and the lingual framemember are provided as a prefabricated integral part; and wherein theinner and outer attachment member are configured as a side flapextending along the inner boundary edge respectively the outer boundaryedge and to be attached to the lingual respectively facial frame member.114. The method according to claim 111, wherein the inner and outerattachment member are configured as a double side flap extending alongthe inner boundary edge respectively the outer boundary edge; whereinthe lingual and facial frame part are configured with a plate part; andwherein the double side flap comprises a first flap part and a secondflap part parallel to the first flap part and at a distance from thefirst flap part to define, between the first and second flap part, a gapconfigured to receive the plate part of the lingual respectively facialframe part.
 115. The method according to claim 111, wherein, in theproviding step, two bristled sheet parts are obtained, each bristledsheet part: being delimited by a said inner boundary edge and a saidouter boundary edge, extending along the length axis at a distance fromthe length axis; being an integral part with a said lingual frame memberand facial frame member both being bow-shaped along a respective bowcurvature; and comprising, on the inner boundary edge, an said innerattachment member extending along the inner boundary edge and attachedto the lingual frame member, and, on the outer boundary edge, a saidouter attachment member extending along the outer boundary edge andattached to the facial frame member; wherein the facial frame memberassociated to a first of said two bristled sheet parts is provided witha male or female part of a first snap connection and the facial framemember associated to a second of said two bristled sheet parts isprovided with the female respectively male part of said first snapconnection; and wherein the lingual frame member associated to the firstof said two bristled sheet parts is provided with a male or female partof a second snap connection and the facial frame member associated tothe second of said two bristled sheet parts is provided with a femalerespectively male part of said second snap connection.
 116. The methodaccording to claim 111, wherein the bow curvatures of the lingual andfacial frame members, as obtained with the bristled sheet part in theproviding step, are wider than the final curvature; and wherein, in thetransforming step, the bow curvatures are narrowed to correspondencewith the final curvature.
 117. The method according to claim 111,wherein the lingual and facial frame members are resilient and have arelieved condition in which the frame members are stress-less and have abow curvature corresponding to the final curvature of the recess wall;wherein a pre-biasing step takes place before or during the providingstep; wherein, in the pre-biasing step, the frame members arepre-tensioned from the relieved condition to a pre-tensioned conditionin which the bow curvatures of the frame members correspond to theinitial curvature of the bristled sheet part and in which the framemembers have a pre-tension acting in a direction to return the framemembers to their relieved condition; and wherein, in the transformingstep, the bow curvatures are narrowed by releasing the pre-tension ofthe frame members.
 118. The method according to claim 111, wherein, inthe providing step, two said bristled sheet parts are obtained andwherein the attachment members of the first and second sheet part areattached to each other by thermally welding.
 119. The method accordingto claim 103, wherein, in the providing step, two said bristled sheetparts are obtained as a single part having a transition area connectinga first of the two bristled sheet part integrally with a second of thetwo bristled sheet part; wherein the transition area is configured toallow the two bristled sheet parts to be folded with respect to eachother from a first position in which the two bristled sheet parts arealigned to a second position in which the two sheet bristled parts arefolded over each other; and wherein, in a folding step, the bristledsheet parts are folded with respect to each other from the first to thesecond position.
 120. The method according to claim 103, wherein thefinal U-shape has an internal width in the range of 0 to 20 mm; whereinthe final U-shape has an internal height in the range of 3 to 20 mm; andwherein the bristled sheet part has a thickness in the range of 0.5 to 3mm.
 121. A method of manufacturing a mouthpiece of the type comprising abody provided with at least one recess delimited by a recess wall linedwith a plurality of bristles extending from the recess wall into therecess, the recess wall defining an arch-shaped length axis and, viewedtransverse to the length axis, a U-shaped cross-sectional shape andbeing configured for encompassing a plurality of dental positions alonga dental arch; wherein the recess wall is manufactured according toclaim 103; and wherein the body further comprises at least one pressurechamber configured for containing a fluid under pressure and wherein thebody is configured to deform the recess wall by reciprocatinglyincreasing and decreasing a pressure in the at least one pressurechamber.
 122. A mouthpiece for simultaneously brushing at a plurality ofdental positions, wherein the mouthpiece is of the type comprising abody provided with at least one recess delimited by a recess wall linedwith a plurality of bristles extending from the recess wall into therecess, the recess wall defining an arch-shaped length axis and, viewedtransverse to the length axis, a U-shaped cross-sectional shape andbeing configured for encompassing a plurality of dental positions alonga dental arch; wherein the recess wall is manufactured according toclaim 103; and wherein the body further comprises at least one pressurechamber configured for containing a fluid under pressure and wherein thebody is configured to deform the recess wall by reciprocatinglyincreasing and decreasing a pressure in the at least one pressurechamber.